Gene clustering analysis in human osteoporosis disease and modifications of the jawbone

Skeletal abnormalities, pediatric-onset severe osteoporosis, and multiple fragility fractures in a patient with a novel CTNNB1 de novo variant

We report a case of a patient with a de novo germline heterozygous truncating variant of CTNNB1 gene (c.2172del, p.Tyr724Ter) causing neurodevelopmental disorder with spastic diplegia and visual defects syndrome (NEDSDV) associated with a new clinical feature - severe pediatric-onset osteoporosis and multiple fractures. A functional effect of the identified variant was demonstrated using adipose-tissue derived primary mesenchymal stem cells, where we detected the alteration of CTNNB1mRNA and β-catenin protein levels using real-time PCR and Western blot analysis.

Importance of Metalloproteinase Enzyme Group in Selected Skeletal System Diseases

Bone tissue is a dynamic structure that is involved in maintaining the homeostasis of the body due to its multidirectional functions, such as its protective, endocrine, or immunological role. Specialized cells and the extracellular matrix (ECM) are responsible for the remodeling of specific bone structures, which alters the biomechanical properties of the tissue. Imbalances in bone-forming elements lead to the formation and progression of bone diseases. The most important family of enzymes responsible for bone ECM remodeling are matrix metalloproteinases (MMPs)-enzymes physiologically present in the body's tissues and cells. The activity of MMPs is maintained in a state of balance; disruption of their activity is associated with the progression of many groups of diseases, including those of the skeletal system. This review summarizes the current understanding of the role of MMPs in bone physiology and the pathophysiology of bone tissue and describes their role in specific skeletal disorders. Additionally, this work collects data on the potential of MMPs as bio-markers for specific skeletal diseases.

LncRNA DANCR and miR-320a suppressed osteogenic differentiation in osteoporosis by directly inhibiting the Wnt/β-catenin signaling pathway

Our study aimed to determine how lncRNA DANCR, miR-320a, and CTNNB1 interact with each other and regulate osteogenic differentiation in osteoporosis. qRT-PCR and western blotting were performed to determine the expression of DANCR, miR-320a, CTNNB1, and the osteoporosis- or Wnt/β-catenin pathway-related markers T-cell factor 1 (TCF-1), runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). Interactions between CTNNB1, DANCR, and miR-320a were predicted by bioinformatics approaches and validated using a luciferase assay. Osteoblastic phenotypes were evaluated by ALP staining, ALP activity assay and Alizarin Red staining. The bilateral ovariectomy method was used to establish an in vivo osteoporosis model. Bone morphological changes were examined using hematoxylin and eosin (H&E) and Alcian Blue staining. The expression levels of DANCR and miR-320a in BMSCs derived from osteoporosis patients were upregulated, whereas CTNNB1 expression was downregulated compared with that in healthy controls. Importantly, we demonstrated that miR-320a and DANCR acted independently from each other and both inhibited CTNNB1 expression, whereas the inhibitory effect was additive when miR-320a and DANCR were cooverexpressed. Moreover, we found that DANCR overexpression largely abrogated the effect of the miR-320a inhibitor on CTNNB1 expression and the Wnt/β-catenin signaling pathway in BMSCs during osteogenic differentiation. We further confirmed the results above in BMSCs derived from an osteoporosis animal model. Taken together, our findings revealed that DANCR and miR-320a regulated the Wnt/β-catenin signaling pathway during osteogenic differentiation in osteoporosis through CTNNB1 inhibition. Our results highlight the potential value of DANCR and miR-320a as promising therapeutic targets for osteoporosis treatment.

Two non-coding RNAs are potential targets for reducing bone loss in post-menopausal osteoporosis. Bones are constantly being remodeled; when resorption outpaces generation of new bone, bones are weakened, causing osteoporosis and leading to decreased quality of life and injuries. Although treatments exist, they often have undesirable side effects, and new treatments are needed. The molecular basis of the changes that accompany osteoporosis are poorly understood. Da Zhong at the Xiangya Hospital of Central South University in Changsha, China, and co-workers investigated how two non-coding RNAs, small molecules that regulate gene expression, are involved in the progression of post-menopausal osteoporosis. They found that levels of both molecules are increased in osteoporosis, and that silencing them increases building of new bone, key to maintaining bone strength. These results illuminate a potential new direction in treatments for osteoporosis.

MiR-16-5p regulates postmenopausal osteoporosis by directly targeting VEGFA

In this study, we used bioinformatics tools, and experiments with patient tissues and human mesenchymal stem cells (hMSCs) to identify differentially regulated genes (DEGs) and microRNAs (miRNAs) that promote postmenopausal osteoporosis. By analyzing the GSE56815 dataset from the NCBI GEO database, we identified 638 DEGs, including 371 upregulated and 267 downregulated genes, in postmenopausal women with low bone density. Enrichment and protein-protein interaction network analyses showed that TP53, RPS27A, and VEGFA were the top three hub genes with the highest degree of betweenness and closeness centrality. TargetScanHuman and DIANA software analyses and dual luciferase reporter assays confirmed that miR-16a-5p directly targets the 3'UTR of VEGFA. Postmenopausal patients with osteoporosis showed higher miR-16-5p and lower VEGFA levels than those without osteoporosis (n=10 each). VEGFA levels were higher in miR-16-5p knockdown hMSCs and were reduced in miR-16-5p-overexpressing hMSCs. mRNA expression of osteogenic markers, ALP, OCN, and RUNX2, as well as calcium deposition based on Alizarin red staining, correlated inversely with miR-16-5p levels and correlated positively with VEGFA levels. These findings suggest that miR-16-5p suppresses osteogenesis by inhibiting VEGFA expression and is a promising target for postmenopausal osteoporosis therapy.

Development of Antiresorptive Agent-Related Osteonecrosis of the Jaw After Dental Implant Removal: A Case Report

Dental implant treatment is a highly predictable therapy, but when potentially lethal symptoms or complications occur, dentists must remove the implant fixture. Recently, reports on antiresorptive agent-related osteonecrosis of the jaw have increased in the field of dental implants, although the relationship between dental implant treatment and antiresorptive agents remains unclear. Here, we report a case of antiresorptive agent-related osteonecrosis of the jaw that developed after dental implant removal. A 67-year-old Japanese woman with a medical history of osteoporosis and 7 years of oral bisphosphonate treatment was referred to our hospital with a chief complaint of painful right mandibular bone exposure. A family dentist removed the dental implants from the right mandible using a trephine drill without flap elevation in August 2016. However, the healing was impaired; she was referred to our hospital 3 months after the procedure. We performed a sequestrectomy of the mandible under general anesthesia. In conclusion, this patient's course has two important implications: First, the removal of dental implants from patients who are prescribed oral bisphosphonates for long durations can cause antiresorptive agent-related osteonecrosis of the jaw. Second, meticulous procedures are required to prevent and treat the development of antiresorptive agent-related osteonecrosis of the jaw after dental implant removal.

SATB2-Nanog axis links age-related intrinsic changes of mesenchymal stem cells from craniofacial bone

Bone mesenchymal stem cells (BMSCs) senescence contributes to age-related bone loss. The alveolar bone in jaws originates from neural crest cells and possesses significant site- and age-related properties. However, such intrinsic characteristics of BMSCs from alveolar bone (AB-BMSCs) and the underlying regulatory mechanisms still remain unknown. Here, we found that the expression of special AT-rich binding protein 2 (SATB2) in human AB-BMSCs significantly decreased with aging. SATB2 knockdown on AB-BMSCs from young donors displayed these aging-related phenotypes in vitro. Meanwhile, enforced SATB2 overexpression could rejuvenate AB-BMSCs from older donors. Importantly, satb2 gene- modified BMSCs therapy could prevent the alveolar bone loss during the aging of rats. Mechanistically, the stemness regulator Nanog was identified as the direct transcriptional target of SATB2 in BMSCs and functioned as a downstream mediator of SATB2. Collectively, our data reveal that SATB2 in AB-BMSCs associates with their age-related properties, and prevents AB-BMSCs senescence via maintaining Nanog expression. These findings highlight the translational potential of transcriptional factor-based cellular reprogramming for anti-aging therapy.

Multi-Elemental Profiling of Tibial and Maxillary Trabecular Bone in Ovariectomised Rats

Atomic minerals are the smallest components of bone and the content of Ca, being the most abundant mineral in bone, correlates strongly with the risk of osteoporosis. Postmenopausal women have a far greater risk of suffering from OP due to low Ca concentrations in their bones and this is associated with low bone mass and higher bone fracture rates. However, bone strength is determined not only by Ca level, but also a number of metallic and non-metallic elements in bone. Thus, in this study, the difference of metallic and non-metallic elements in ovariectomy-induced osteoporosis tibial and maxillary trabecular bone was investigated in comparison with sham operated normal bone by laser ablation inductively-coupled plasma mass spectrometry using a rat model. The results demonstrated that the average concentrations of ²⁵Mg, ²⁸Si, ³⁹K, ⁴⁷Ti, ⁵⁶Fe, ⁵⁹Co, ⁷⁷Se, ⁸⁸Sr, ¹³⁷Ba, and ²⁰⁸Pb were generally higher in tibia than those in maxilla. Compared with the sham group, Ovariectomy induced more significant changes of these elements in tibia than maxilla, indicating tibial trabecular bones are more sensitive to changes of circulating estrogen. In addition, the concentrations of ²⁸Si, ⁷⁷Se, ²⁰⁸Pb, and Ca/P ratios were higher in tibia and maxilla in ovariectomised rats than those in normal bone at all time-points. The present study indicates that ovariectomy could significantly impact the element distribution and concentrations between tibia and maxilla.

Gene Expression of Human Mesenchymal Stem Cells Cultured on Titanium Dental Implant Surfaces

OBJECTIVE

The study shows how the influence of titanium surfaces on human mesenchymal stem cells differentiates toward osteocytes lineage and how, after growth, on machined titanium disk or etched titanium disk, changes, in gene expression for RUNX1, CTNNB1, SP7, and DLX5.

METHODS

Genes were analyzed by means of quantitative real-time polimerase chain reaction. Osseo genic lineage differentiation was also tested by means of the catenin-β1 immunofluorescence, induced osteoblasts, which represented the internal control.

RESULTS

The RUNX1 and SP7 expressions in the induced osteoblasts prove to be different, compared with cells cultured on metallic supports. Moreover, the levels of expression of the runt-related transcription factor 1 and the osterix appeared more down-regulated in cells that grew on a machined titanium surface. In the present experimental model, mRNA expression of DLX5 and CTNNB1 in human mesenchymal stem cells, cultured on each of the titanium surfaces, showed no differences, compared with osteoblast-induced cells. The immunofluorescence scores, for protein expression of beta-catenin in human mesenchymal stem cell treated cells, illustrates significantly improved results with the etched surface.

CONCLUSIONS

Present results suggested that different titanium surfaces might induce some differences in terms of gene expression. The only gene analyzed, which proved significant differences between the 2 titanium supports, was SP7; however, the other 3 genes indicating the existence of differences between the 2 titanium groups.

Interactions between osteopontin and vascular endothelial growth factor: Implications for skeletal disorders

Osteopontin (OPN) and vascular endothelial growth factor (VEGF) are characterized by a convergence in function for maintaining the homeostasis of the skeletal and renal systems (the bone-renal-vascular axis regulates bone metabolism). The two cytokines contribute to bone remodeling, dental healing, kidney function, and the adjustment to microgravity. Often, they are co-expressed or one molecule induces the other, however, in some settings OPN-associated pathways and VEGF-associated pathways are distinct. In bone remodeling, OPN and VEGF are regulated under the influence of growth factors and hormones, hypoxia and inflammation, the micro-environment, and various physical forces. Their abundance can be affected by drug treatment. OPN and VEGF are variably associated with kidney disease. Their balanced levels are critical for restoring endothelial cell function and ameliorating the adverse effects of microgravity. Here, we review the relevant 83 papers of 257 articles published, and listed in PubMed under the key words OPN and VEGF.

Differentiation, apoptosis, and GM-CSF receptor expression of human gingival fibroblasts on a titanium surface treated by a dual acid-etched procedure

OBJECTIVES

Analysis of the effects of titanium surface properties on the biological behavior of human gingival fibroblasts (HGFs).

MATERIALS AND METHODS

HGFs were in vitro cultured on a titanium surface modified by a dual acid-etched procedure and on a control machined surface. Cell adhesion, proliferation, apoptosis, production of certain extracellular matrix (ECM) proteins, and expression of granulocyte macrophage-colony stimulating factor receptor (GM-CSFR) were investigated using in each experiment a total of 18 samples for each titanium surface.

RESULTS

Cell attachment at 3 h of culture was statistically significantly higher on the etched surface. HGF growth increased on both surfaces during the entire experimental period and at day 14 of culture cell proliferation was statistically significantly higher on the treated surface than on the control. No statistically significant differences in percentage of apoptosis events were observed between the surfaces. ECM protein production increased progressively over time on both surfaces. A statistically significant deposition was observed at day 7 and 14 for collagen I and only at day 14 for fibronectin and tenascin, when compared to the baseline. GM-CSFR registered a positive expression on both surfaces, statistically significant at day 14 on the etched surface in comparison with the machined one.

CONCLUSIONS

Data showed that titanium surface microtopography modulates in vitro cell response and phenotypical expression of HGFs. The etched surface promoted a higher cell proliferation and differentiation improving the biological behavior of HGFs.

CLINICAL RELEVANCE

Results suggest a possible beneficial effect of surface etching modification on peri-implant biological integration and soft tissue healing which is critical for the formation of a biological seal around the neck of dental implants.

Interactions between osteopontin and vascular endothelial growth factor: Implications for cancer

For this comprehensive review, 257 publications with the keywords "osteopontin" or "OPN" and "vascular endothelial growth factor" or "VEGF" in PubMed were screened (time frame from year 1996 to year 2014). 37 articles were excluded because they were not focused on the interactions between these molecules, and papers relevant for transformation-related phenomena were selected. Osteopontin (OPN) and vascular endothelial growth factor (VEGF) are characterized by a convergence in function for regulating cell motility and angiogenesis, the response to hypoxia, and apoptosis. Often, they are co-expressed or one molecule induces the other, however, in some settings OPN-associated pathways and VEGF-associated pathways are distinct. Their relationships affect the pathogenesis in cancer, where they contribute to progression and angiogenesis and serve as markers for poor prognosis. The inhibition of OPN may reduce VEGF levels and suppress tumor progression. In vascular pathologies, these two cytokines mediate remodeling, but may also perpetuate inflammation and narrowing of the arteries. OPN and VEGF are elevated and contribute to vascularization in inflammatory diseases.

A single nucleotide polymorphism in the TGF-β1 gene (rs1982073 C>T) may contribute to increased risks of bone fracture, osteoporosis, and osteoarthritis: a meta-analysis

Genetic factors have been shown to be of great importance for the pathogenesis of bone diseases, such as fracture, osteoporosis (OP), and osteoarthritis (OA). However, published studies on the correlations of transforming growth factor-β1 (TGF-β1) gene polymorphisms with bone diseases have been hampered by small sample sizes or inconclusive findings. We hence aimed at examining the relationships between a single nucleotide polymorphism in the TGF-β1 gene (rs1982073 C>T) with bone fracture, OP, and OA risks in this meta-analysis. A systematic electronic search of literature was conducted to identify all published studies in English or Chinese on the association between the TGF-β1 gene and fracture, OP, or OA risks. Data were abstracted independently by two reviewers. To investigate the strength of this relationship, crude odds ratios with 95 % confidence intervals were used. An updated meta-analysis based on nine independent case-control studies were chosen (patients with fracture, OP, or OA = 1569; healthy controls = 1638). Results identified a higher frequency of rs1982073 C>T in patients with fracture, OP, or OA than in healthy controls. Ethnicity and genotyping method-stratified analysis under both models implied that the rs1982073 C>T polymorphism was positively correlated with the risk of fracture, OP, and OA among Asians under detection via the non-PCR-RFLP method. Disease-stratified results yielded that rs1982073 C>T may increase the risk of fracture, OP, and OA under the allele model, but was only significantly related to OP under the dominant model. According to the sample size-stratified analysis, subjects with the rs1982073 C>T polymorphism in the allele model were more likely to develop the three bone diseases in both the small and large sample size groups, and only in the large sample size under the dominant model. Our findings show that TGF-β1 rs1982073 C>T has a modest effect in increasing susceptibility to bone fracture, OP, and OA.

A gene network bioinformatics analysis for pemphigoid autoimmune blistering diseases

OBJECTIVE

In this theoretical study, a text mining search and clustering analysis of data related to genes potentially involved in human pemphigoid autoimmune blistering diseases (PAIBD) was performed using web tools to create a gene/protein interaction network.

METHODS

The Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database was employed to identify a final set of PAIBD-involved genes and to calculate the overall significant interactions among genes: for each gene, the weighted number of links, or WNL, was registered and a clustering procedure was performed using the WNL analysis. Genes were ranked in class (leader, B, C, D and so on, up to orphans). An ontological analysis was performed for the set of 'leader' genes.

RESULTS

Using the above-mentioned data network, 115 genes represented the final set; leader genes numbered 7 (intercellular adhesion molecule 1 (ICAM-1), interferon gamma (IFNG), interleukin (IL)-2, IL-4, IL-6, IL-8 and tumour necrosis factor (TNF)), class B genes were 13, whereas the orphans were 24. The ontological analysis attested that the molecular action was focused on extracellular space and cell surface, whereas the activation and regulation of the immunity system was widely involved.

CONCLUSIONS

Despite the limited knowledge of the present pathologic phenomenon, attested by the presence of 24 genes revealing no protein-protein direct or indirect interactions, the network showed significant pathways gathered in several subgroups: cellular components, molecular functions, biological processes and the pathologic phenomenon obtained from the Kyoto Encyclopaedia of Genes and Genomes (KEGG) database.

CLINICAL RELEVANCE

The molecular basis for PAIBD was summarised and expanded, which will perhaps give researchers promising directions for the identification of new therapeutic targets.

Expression of SP7, RUNX1, DLX5, and CTNNB1 in human mesenchymal stem cells cultured on xenogeneic bone substitute as compared with machined titanium

PURPOSE

The aim of this research was to investigate the gene expression profile of 4 transcription factors in human mesenchymal stem cells (hMSC) cultured with a xenogeneic bone substitute and a support of machined titanium.

MATERIAL AND METHODS

In vitro studies were performed on hMSC cells, which grew in contact with cortical porcine bone and machined titanium disks for 10 days. RNA quantification for genes DLX5, CTNNB1, RUNX1, and SP7 was assessed by quantitative real-time polymerase chain reaction. For cells supported by titanium, immunocytochemistry of osteocalcin (OC) was also performed.

RESULTS

In the osteoblast-induced cells (OIC), DLX5, CTNNB1, and RUNX1 were significantly upregulated (+2.38-, +3.51-, and +7.08-fold, respectively), whereas SP7 was downregulated (-26.32-fold). None of the genes seemed to be upregulated or downregulated by the corticocancellous porcine bone. In cells grown on titanium support, DLX5 and RUNX1 were respectively upregulated (+3.12-fold) and downregulated (-2.14-fold). For titanium support, the presence of both catenin beta-1 and OC was verified.

CONCLUSION

The 2 genes RUNX1 and SP7 resulted differently expressed in cells cultured on metallic supports if compared with the expression recorded for OIC. An induction of the osteogenic phenotype was observed when cells were cultured on machined titanium, but not on xenogeneic material.

Efficacy of systemic bisphosphonate delivery on osseointegration of implants under osteoporotic conditions: lessons from animal studies

BACKGROUND

The aim was to systematically review the role of systemic bisphosphonate (BP) delivery on osseointegration of implants under osteoporotic conditions.

METHODS

The addressed focused question was "Does systemic BP delivery enhance osseointegration of implants under osteoporotic conditions?" PubMed/MEDLINE and Google-Scholar databases were searched from 1994 up to and including December 2013 using different combinations of the following keywords: "bone to implant contact", "implant", "bisphosphonate", "osseointegration" and "osteoporosis". Review articles, case-reports, commentaries, letters to the Editor, unpublished articles and articles published in languages other than English were excluded.

RESULTS

Fifteen animal studies fulfilled our eligibility criteria. Osteoporotic conditions were induced via bilateral ovariectomy (OVX). BPs used in the studies were ibandronate, zoledronic acid and alendronate. Results from 12 studies showed that systemic BP delivery significantly increased bone volume and bone-to-implant contact under osteoporotic conditions. Two studies reported no significant difference in osseointegration among OVX animals with and without systemic BP delivery. In one study, systemic BP delivery negatively influenced implant osseointegration. Rough-surfaced and polished implants were used in 11 and one study respectively. In 3 studies implant surface characteristics remained unclear.

CONCLUSION

Within the limits of the present study, it is concluded that systemic BP delivery enhances implant osseointegration in animals with induced osteoporotic conditions. However, in a clinical scenario, the potential risk of BP related ONJ in osteoporotic patients undergoing dental implant therapy cannot be disregarded.

Five-year outcome of bone remodelling around implants in the maxillary sinus: assessment of differences between implants placed in autogenous inlay bone blocks and in ungrafted maxilla

The placement of implants in the posterior maxillary area is considered a reliable procedure, offering recognized rehabilitative advantages. The aim of this study was to evaluate the performance of dental implants placed in the sinus floor augmented with a block autograft by comparing the outcomes over 5 years with those of dental implants positioned in non-augmented bone. This retrospective cohort study included 16 patients who had undergone prosthetic rehabilitation supported by dental implants between 2000 and 2006. One implant per patient was included and assigned to one of two predictor groups: grafted versus ungrafted maxillary sinus. Changes in marginal bone level (MBL) and apical bone level (ABL) over time, at 1, 3, and 5 years, were the primary outcome variables. Appropriate pair-wise comparison tests were performed. No significant differences were seen with regard to ABLs and among times between the grafted group (nine implants) and the ungrafted group (seven implants). Significant marginal bone resorption was found over time, primarily at the buccal aspect, in both study groups. The bone surrounding the apex of dental implants appeared stable after sinus augmentation in the grafted area. The behaviour of the two groups with regard to loss of MBLs over time was very similar.

A 5-Year Implant Follow-Up in Maxillary and Mandibular Horizontal Osseous Onlay Grafts and Native Bone

The purpose of this study is to analyze marginal bone levels (MBLs) around dental implants positioned in the upper and lower jaw with or without horizontal onlay grafting procedures, and to survey implant survival with a follow-up of 5 years. Seventeen patients were surveyed in the present retrospective chart review. A total of 27 dental implants positioned in pristine bone and 21 in horizontally grafted bone were enrolled. MBLs were recorded for 4 aspects during a radiologic survey of 5 years. Significant differences were searched for among times and surgical procedures with paired and unpaired comparison tests, respectively, and survival rates were calculated for the 2 groups. In the maxilla, no statistically-significant differences between pristine and augmented groups were obtained; the time comparisons for pristine implants showed an affection of palatal, mesial, and distal sides, whereas the resorption around implants placed into horizontally grafted bone of anterior maxilla seemed to be limited just to buccal and distal aspects. Comparisons with the pristine horizontal procedure revealed that just the buccal sides were involved. The analysis of time comparisons attested to a continuous alveolar bone remodeling during the entire time of the survey for the pristine group. Given the extremely unfavorable resorption at the buccal aspect of the augmented areas, clinicians should reserve dental implant positioning into horizontal bone graft to selected patients, in whom it may represent one of the last opportunities of rehabilitation with a fixed prosthesis.

A 5-year clinical and computerized tomographic implant follow-up in sinus-lifted maxillae and native bone

OBJECTIVES

The present study analysed apical and marginal bone remodelling around dental implants placed in both maxillary (sinus elevated with particulated autogenous osseous graft) and corresponding native bone areas, with a follow-up of 5 years. The clinical survival of implants was also observed.

MATERIALS AND METHODS

In this retrospective chart review, 27 patients were enrolled, with 55 dental implants inserted from 2000 to 2006, 26 of which were followed (one implant per patient); if required, patients were treated via sinus lift with autogenous bone and particulate technique. The internal controls were implants positioned in native areas beneath the sinus. Radiologic survey was assessed via computerized tomographic analysis measuring apical bone level (ABL) and marginal bone level (MBL), at 1- (T1 ), 3- (T2 ) and 5 years (T3 ), around implants (buccal, b; palatal, p; mesial, m; and distal sides, d). Clinical probing depth (CPD) and clinical attachment level (CAL) for all the four peri-implant aspects were measured. Cumulative survival rate (CSR) and survival rate (SR) of implants were calculated. Significances for paired and unpaired comparisons were searched for.

RESULTS

A significant degree of apical resorption was recorded between T1 and T3 for the mesial particulate group; again, a significant difference was discovered between the native and particulate procedures for mABL. A further feature was discovered for the particulate procedure, for which ABLs resulted negative at least for three of the aspects. Regarding MBL measurements, similar behaviours were revealed using time-comparison analysis for the two procedures at the buccal aspect. Comparisons among diameters, irrespective of the procedure, showed that resorption times for the bMBL were shorter as the diameter of the implant became wider. The implant CSR was 92% in native areas (two failures/25 implants) and 93.3% in sinuses lifted with particulate bone (two failures/30 implants).

CONCLUSIONS

The results suggest that a protrusion of the implant apices into augmented sinus lift occurred, whereas the bone remodelling of the coronal areas was not influenced by the events in the maxillary sinus. A diameter ranging from 4 to 5 mm might better guarantee a conservation of marginal peri-implant bone level compared with implants with smaller diameters.