Bone-to-implant contact around immediately loaded direct laser metal-forming transitional implants in human posterior maxilla

Additive Manufacturing Titanium Dental Implants Placed in Sinuses Grafted with 70HA:30-TCP: A One-Year Retrospective Study for Evaluation of Survival Rate

The present short-term retrospective study evaluated the implant survival rate and peri-implant bone loss around additive-manufactured titanium implants placed in sinuses grafted with Plenum Osshp (Plenum Bioengenharia, Jundia, SP, Brazil) (70HA:30β-TCP) material. A total of 39 implants were inserted after 23 sinus floor elevation procedures in 16 consecutive patients. Prosthetic rehabilitation included fixed partial prostheses (three units), single crowns (eleven units), and fixed full arches (three units). Clinical and radiographic parameters of implant-supported restorations were evaluated after at least one year of occlusal loading. The implant-crown success criteria included the absence of pain, suppuration, and clinical mobility, an average distance between the implant shoulder and the first visible bone contact (DIB) < 1.0 mm from the initial surgery, and the absence of prosthetic complications at the implant-abutment interface. The overall cumulative implant survival rate was 97.43%. No prosthetic complications at the implant-abutment interface were reported. After one year, the mean DIB was 0.23 mm ± 0.14. Within the limits of this retrospective study, it can be concluded that 70 HA:30 β-TCP allowed stable and reliable bone support to maintain healthy conditions around titanium dental implants produced by additive manufacturing.

Osseointegration of implant surfaces in metabolic syndrome and type-2 diabetes mellitus

This in vivo study evaluated the bone healing response around endosteal implants with varying surface topography/chemistry in a preclinical, large transitional model induced with metabolic syndrome (MS) and type-2 diabetes mellitus (T2DM). Fifteen Göttingen minipigs were randomly distributed into two groups: (i) control (normal diet, n = 5) and (ii) O/MS (cafeteria diet for obesity induction, n = 10). Following obesity induction, five minipigs from the obese/metabolic syndrome (O/MS) group were further allocated, randomly, into the third experimental group: (iii) T2DM (cafeteria diet + streptozotocin). Implants with different surface topography/chemistry: (i) dual acid-etched (DAE) and (ii) nano-hydroxyapatite coating over the DAE surface (NANO), were placed into the right ilium of the subjects and allowed to heal for 4 weeks. Histomorphometric evaluation of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO) within implant threads were performed using histomicrographs. Implants with NANO surface presented significantly higher %BIC (~26%) and %BAFO (~35%) relative to implants with DAE surface (%BIC = ~14% and %BAFO = ~28%, p < .025). Data as a function of systemic condition presented significantly higher %BIC (~28%) and %BAFO (~42%) in the control group compared with the metabolically compromised groups (O/MS: %BIC = 14.35% and %BAFO = 26.24%, p < .021; T2DM: %BIC = 17.91% and %BAFO = 26.12%, p < .021) with no significant difference between O/MS and T2DM (p > .05). Statistical evaluation considering both factors demonstrated significantly higher %BIC and %BAFO for the NANO surface relative to DAE implant, independent of systemic condition (p < .05). The gain increase of %BIC and %BAFO for the NANO compared with DAE was more pronounced in O/MS and T2DM subjects. Osseointegration parameters were significantly reduced in metabolically compromised subjects compared with healthy subjects. Nanostructured hydroxyapatite-coated surfaces improved osseointegration relative to DAE, regardless of systemic condition.

3D printed dental implants with a porous structure: The in vitro response of osteoblasts, fibroblasts, mesenchymal stem cells, and monocytes

AIMS

The first aim of this study was to characterize the surface topography of a novel 3D-printed dental implant at the micro- and macro-level. Its second aim was to evaluate the osteogenic, angiogenic, and immunogenic responses of human oral osteoblasts (hOBs), gingival fibroblasts (hGFs), mesenchymal stem cells (hAD-MSCs), and monocytes to this novel implant surface.

METHODS

A 3D-printed Ti-6Al-4 V implant was produced by selective laser melting and subjected to organic acid etching (TEST). It was then compared to a machined surface (CTRL). Its biological properties were evaluated via cell proliferation assays, morphological observations, gene expression analyses, mineralization assessments, and collagen quantifications.

RESULTS

Scanning electron microscopy analysis showed that the TEST group was characterized by a highly interconnected porous architecture and a roughed surface. The morphological observations showed good adhesion of cells cultured on the TEST surface, with a significant increase in hOB growth. Similarly, the gene expression analysis showed significantly higher levels of osseointegration biomarkers. Picrosirius staining showed a slight increase in collagen production in the TEST group compared to the CTRL group. hAD-MSCs showed an increase in endothelial and osteogenic commitment-related markers. Monocytes showed increased mRNA synthesis related to the M2 (anti-inflammatory) macrophagic phenotype.

CONCLUSIONS

Considering the higher interaction with hOBs, hGFs, hAD-MSCs, and monocytes, the prepared 3D-printed implant could be used for future clinical applications.

CLINICAL RELEVANCE

This study demonstrated the excellent biological response of various cells to the porous surface of the novel 3D-printed implant.

Osseointegration of functionally graded Ti6Al4V porous implants: Histology of the pore network

The additive manufacturing of titanium into porous geometries offers a means to generate low-stiffness endosseous implants with a greater surface area available for osseointegration. In this work, selective laser melting was used to produce gyroid-based scaffolds with a uniform pore size of 300 μm or functionally graded pore size from 600 μm to 300 μm. Initial in vitro assessment with Saos-2 cells showed favourable cell proliferation at pore sizes of 300 and 600 μm. Following implantation into rabbit tibiae, early histological observations at four weeks indicated some residual inflammation alongside neovessel infiltration into the scaffold interior and some early apposition of mineralized bone tissue. At twelve weeks, both scaffolds were filled with a mixture of adipocyte-rich marrow, micro-capillaries, and mineralized bone tissue. X-ray microcomputed tomography showed a higher bone volume fraction (BV/TV) and percentage of bone-implant contact (BIC) in the implants with 300 μm pores than in the functionally graded specimens. In functionally graded specimens, localized BV/TV measurement was observed to be higher in the innermost region containing smaller pores (estimated at 300-400 μm) than in larger pores at the implant exterior. The unit cell topology of the porous implant was also observed to guide the direction of bone ingrowth by conducting along the implant struts. These results suggest that in vivo experimentation is necessary alongside parametric optimization of functionally graded porous implants to predict short-term and long-term bone apposition.

Human Histological Analysis of Early Bone Response to Immediately Loaded Narrow Dental Implants with Biphasic Calcium Phosphate® Grid-Blasted Surface Treatment: A Case Report

Implant surface topography using bioactive material provides faster bone-to-implant healing. This histological report described the analysis of human bone tissue around an immediately loaded implant, with BPC^® (Biphasic Calcium Phosphate) grit-blasted surface treatment, after two months of healing. Two temporary mini-implants (2.8 × 10 mm) with BPC^® grit-blasting surfaces were placed and immediately loaded to retain a complete interim denture. After a 60-day healing period, one mini-implant was removed for histologic analysis. The ground section showed the whole implant surrounded by healthy peri-implant tissues. Implant surface presented a close contact with newly formed bone, showing some areas of osteoblasts secreting mineral matrix. The ground section depicted a bone contact of 60.3 + 8.5%. The BPC^® grit-blasted surface was biocompatible and enabled the osseointegration process after a short-term period.

Bacterial Adhesion Strength on Titanium Surfaces Quantified by Atomic Force Microscopy: A Systematic Review

Few studies have been able to elucidate the correlation of factors determining the strength of interaction between bacterial cells and substrate at the molecular level. The aim was to answer the following question: What biophysical factors should be considered when analyzing the bacterial adhesion strength on titanium surfaces and its alloys for implants quantified by atomic force microscopy? This review followed PRISMA. The search strategy was applied in four databases. The selection process was carried out in two stages. The risk of bias was analyzed. One thousand four hundred sixty-three articles were found. After removing the duplicates, 1126 were screened by title and abstract, of which 57 were selected for full reading and 5 were included; 3 had a low risk of bias and 2 moderated risks of bias. (1) The current literature shows the preference of bacteria to adhere to surfaces of the same hydrophilicity. However, this fact was contradicted by this systematic review, which demonstrated that hydrophobic bacteria developed hydrogen bonds and adhered to hydrophilic surfaces; (2) the application of surface treatments that induce the reduction of areas favorable for bacterial adhesion interfere more in the formation of biofilm than surface roughness; and (3) bacterial colonization should be evaluated in time-dependent studies as they develop adaptation mechanisms, related to time, which are obscure in this review.

Exploring the Importance of Corticalization Occurring in Alveolar Bone Surrounding a Dental Implant

Several measures describing the transformation of trabecular bone to cortical bone on the basis of analysis of intraoral radiographs are known (including bone index or corticalization index, CI). At the same time, it has been noted that after functional loading of dental implants such transformations occur in the bone directly adjacent to the fixture. Intuitively, it seems that this is a process conducive to the long-term maintenance of dental implants and certainly necessary when immediate loading is applied. The authors examined the relationship of implant design features to marginal bone loss (MBL) and the intensity of corticalization over a 10-year period of functional loading. This study is a general description of the phenomenon of peri-implant bone corticalization and an attempt to interpret this phenomenon to achieve success of implant treatment in the long term. Corticalization significantly increased over the first 5-year functional loading (CI from 200 ± 146 initially to 282 ± 182, p < 0.001) and maintained a high level (CI = 261 ± 168) in the 10-year study relative to the reference bone (149 ± 178). MBL significantly increased throughout the follow-up period—5 years: 0.83 ± 1.26 mm (p < 0.001), 10 years: 1.48 ± 2.01 mm (p < 0.001). MBL and radiographic bone structure (CI) were evaluated in relation to intraosseous implant design features and prosthetic work performed. In the scope of the study, it can be concluded that the phenomenon of peri-implant jawbone corticalization seems an unfavorable condition for the future fate of bone-anchored implants, but it requires further research to fully explain the significance of this phenomenon.

Modelling the resonant frequency associated with the spatio-temporal evolution of the bone-dental implant interface

Dental implant stability is greatly affected by the mechanical properties of the bone-implant interface (BII), and it is key to long-term successful osseointegration. Implant stability is often evaluated using the Resonant Frequency Analysis (RFA) method, and also by the quality of this interface, namely the bone-implant contact (BIC). True to this day, there is a scarcity of models tying BIC, RFA and a spatially and mechanically evolving BII. In this paper, based on the contact/distance osteogenesis concept, a novel numerical spatio-temporal model of the implant, surrounding bone and evolving interface, was developed to assess the evolution of the interfacial stresses on the one hand and the corresponding resonant frequencies on the other. We postulate that, since the BIC percentage reaches saturation over a very short time, long before densification of the interface, it becomes irrelevant as to load transmission between the implant and the bone due to the existence of an open gap. Gap closure is the factor that provides continuity between the implant and the surrounding bone. The results of the calculated RFA evolution match and provide an explanation for the multiple clinical observations of a sharp initial decline in RFA, followed by a gradual increase and plateau formation. STATEMENT OF SIGNIFICANCE: A novel three-dimensional numerical model of an evolving bone-dental implant interface (BII) is presented. The spatio-temporal evolution of the bone-implant contact (BIC) and the BII, based on contact/distance (CO/DO) osteogenesis, is modeled. A central outcome is that, until BII maturation into a solid continuous bone (no open gap between CO-DO fronts), the bone-implant load transfer is hampered, irrespective of the BIC. The resonant frequencies' evolution of the jawbone-BII-implant is calculated to reproduce the well-established implant stability analysis based on the Resonant Frequency Analysis. The results resemble those reported clinically, and here too, the determinant transition occurs only after interfacial gap closure. Those results should motivate clinicians to re-consider structural continuity of the BII rather than the BIC only.

A Narrative Review of the Histological and Histomorphometrical Evaluation of the Peri-Implant Bone in Loaded and Unloaded Dental Implants. A 30-Year Experience (1988-2018)

Background: The aim of the present review was to assess the histological and histomorphometrical data from the paper published by our Laboratory on peri-implant bone in dental implants in different loading conditions. Methods: The papers published in different implant loading conditions, in dental implants retrieved from humans, and in the Hard Tissues Research Center of the University of Chieti-Pescara, Italy, were screened on MEDLINE/PubMed, Embase, Scopus, and other electronic databases until 31 December 2018. Only articles that reported the histological and histomorphometrical values of the Bone-Implant Contact (BIC) were selected. Results: The system selection provided a total of 155 papers. The manuscripts included for the narrative review were 57. These papers provided histological and histomorphometrical data. Conclusions: The bone remodeling around dental implants was found to be a dynamic process; loading changed the microstructure of the peri-implant bone; and implants were found to provide a successful function, over several decades, with different range of degrees of BIC in vivo (varying from a little more than 30% to a little more than 90%). Loaded implants presented a 10%-12% higher BIC values when compared to submerged, unloaded implants, and rougher surfaces had, on average, about a 10% higher BIC than machined surfaces.

Immunohistochemical Evaluation of Peri-Implant Soft Tissues around Machined and Direct Metal Laser Sintered (DMLS) Healing Abutments in Humans

Background: Direct metal laser Sintering (DMLS) is an additive manufacturing technique that allows fabrication of dental implants and related components with a highly porous surface. To date, no human studies have investigated the soft tissue adhesion and presence of inflammatory infiltrate with porous DMLS healing abutments (HAs), nor have they compared these with the classic machined ones. Purpose: To evaluate the degree of cell adhesion (integrin expression) and the quantity/quality of inflammatory infiltrate, on HAs with different surfaces; full DMLS, full machined, and hybrid (half DMLS and half machined). Methods: Fifty implant patients were randomly assigned to receive one of these different Has: T1, full DMLS (11 subjects); T2, machined in the upper portion and DMLS in the lower one (10 subjects); T3, DMLS in the upper portion and machined in the lower one (19 subjects); T4, full machined (10 patients). Thirty days after placement, circular sections of soft tissues around HAs were retrieved for immunohistochemical evaluation. Results: With regard to the adhesion molecules, the samples showed different intensity of integrin expression, with a statistically significant difference (p < 0.001) between T1 and the other groups. All the samples were positive for the different clusters related to the inflammatory infiltrate (T lymphocytes, CD3; B lymphocytes, CD20; and macrophages, CD68), but a lower infiltrate was found in T1, with statistically significant differences (p < 0.001) among the groups. Conclusions: The HA surface seems to influence the degree of cell adhesion and the inflammatory infiltrate of the surrounding soft tissues.

Influence of the Thermal Treatment to Address a Better Osseointegration of Ti6Al4V Dental Implants: Histological and Histomorphometrical Study in a Rabbit Model

Background

Pure titanium continues to be the first choice for dental implants and represents the gold standard for their biocompatibility and physical and mechanical characteristics, while the titanium alloy (Ti6Al4V) has good mechanical properties. The surface structure of the titanium oxide layer formation on the surface influences and improves the bone response around dental implants.

Purpose

The purpose of this study is to evaluate the influence of a thermal treatment of Ti6Al4V implant surfaces and the bone healing response in a rabbit model.

Methods

Altogether sixteen implants with same design were inserted into the distal femoral metaphysis. A screw (13 mm long, 4 mm in diameter) was inserted in an implant bed. Each rabbit received two implants, one in the left femur and one in the right femur. The samples were histologically and histomorphometrically evaluated at 8 weeks.

Results

A statistically significant difference (p = 0.000034) was present histologically in the percentages of bone-implant contact (BIC) between the test group (BIC = 69.25±4.49%.) and control group (BIC = 56.25 ± 4.8%) by one-way analysis of variance (ANOVA). Significance was set at p ≤ 0.05.

Conclusions

The outcome of the present study indicates a novel approach to improving bone healing around titanium implants.

Reliable laser fabrication: the quest for responsive biomaterials surface

This review presents current efforts in laser fabrication, focusing on the surface features of biomaterials and their biological responses; this provides insight into the engineering of bio-responsive surfaces for future medical devices.

Scanning Electron Microscope (SEM) Evaluation of the Interface between a Nanostructured Calcium-Incorporated Dental Implant Surface and the Human Bone

Purpose. The aim of this scanning electron microscope (SEM) study was to investigate the interface between the bone and a novel nanostructured calcium-incorporated dental implant surface in humans. Methods. A dental implant (Anyridge^®, Megagen Implant Co., Gyeongbuk, South Korea) with a nanostructured calcium-incorporated surface (Xpeed^®, Megagen Implant Co., Gyeongbuk, South Korea), which had been placed a month earlier in a fully healed site of the posterior maxilla (#14) of a 48-year-old female patient, and which had been subjected to immediate functional loading, was removed after a traumatic injury. Despite the violent trauma that caused mobilization of the fixture, its surface appeared to be covered by a firmly attached, intact tissue; therefore, it was subjected to SEM examination. The implant surface of an unused nanostructured calcium-incorporated implant was also observed under SEM, as control. Results. The surface of the unused implant showed a highly-structured texture, carved by irregular, multi-scale hollows reminiscent of a fractal structure. It appeared perfectly clean and devoid of any contamination. The human specimen showed trabecular bone firmly anchored to the implant surface, bridging the screw threads and filling the spaces among them. Conclusions. Within the limits of this human histological report, the sample analyzed showed that the nanostructured calcium-incorporated surface was covered by new bone, one month after placement in the posterior maxilla, under an immediate functional loading protocol.

Histological Evidence of the Osseointegration of Fractured Direct Metal Laser Sintering Implants Retrieved after 5 Years of Function

Background

Direct metal laser sintering (DMLS) is an additive manufacturing technique that allows the fabrication of dental implants layer by layer through the laser fusion of titanium microparticles. The surface of DMLS implants is characterized by a high open porosity with interconnected pores of different sizes; therefore, it has the potential to enhance and accelerate bone healing. To date, however, there are no histologic/histomorphometric studies in the literature evaluating the interface between bone and DMLS implants in the long-term.

Purpose

To evaluate the interface between bone and DMLS implants retrieved after 5 years of functional loading.

Methods

Two fractured DMLS implants were retrieved from the human jaws, using a 5 mm trephine bur. Both the implants were clinically stable and functioned regularly before fracture. The specimens were processed for histologic/histomorphometric evaluation; the bone-to-implant contact (BIC%) was calculated.

Results

Compact, mature lamellar bone was found over most of the DMLS implants in close contact with the implant surface; the histomorphometric evaluation showed a mean BIC% of 66.1% (±4.5%).

Conclusions

The present histologic/histomorphometric study showed that DMLS implants were well integrated in bone, after 5 years of loading, with the peri-implant bone undergoing continuous remodeling at the interface.

Early Bone Response to Dual Acid-Etched and Machined Dental Implants Placed in the Posterior Maxilla: A Histologic and Histomorphometric Human Study

PURPOSE

To compare the early bone response to implants with dual acid-etched (DAE) and machined (MA) surface, when placed in the posterior human maxilla.

MATERIALS AND METHODS

Fourteen patients received 2 implants in the posterior maxilla: 1 DAE and 1 MA. After 2 months, the implants were retrieved for histologic/histomorphometric evaluation. The bone-to-implant contact (BIC%), bone density in the threaded area (BDTA%), and the bone density (BD%) were calculated. The Wilcoxon matched-pairs signed rank test was used to evaluate differences (BIC%, BDTA%, and BD%) between the surfaces.

RESULTS

In the MA implants, a mean (±SD) BIC%, BDTA%, and BD% of 21.76 (±12.79), 28.58 (±16.91), and 21.54 (±11.67), respectively, was reported. In the DAE implants, a mean (±SD) BIC%, BDTA%, and BD% of 37.49 (±29.51), 30.59 (±21.78), and 31.60 (±18.06), respectively, was reported. Although the mean BIC% of DAE implants value was almost double than that of MA implants, no significant differences were found between the 2 groups with regard to BIC% (P = 0.198) and with regard to BDTA% (P = 0.778) and BD% (P = 0.124).

CONCLUSIONS

The DAE surface increased the periimplant endosseous healing properties in the native bone of the posterior maxilla.

Advanced Implant-Prosthetic Rehabilitation: How to Obtain a Correct Restoration of Both Functions and Aesthetics in Patients with Complex Combined Dental and Maxillofacial Trauma: A Case Report and Topical Review of the Literature

Aim. This study aims to explain the main steps that characterize the implant-prosthetic rehabilitation in complex combined dental and maxillofacial trauma. Material and Methods. A 20-year-old patient reported an extensive facial trauma which also involved the alveolar process of the maxillary bone. The patient reported a maxillofacial fracture and the loss of teeth 1.3, 1.2, 1.1, and 2.1. A "Le Fort" type 2 fracture was also reported, with the malar bone involvement. After reduction and containment of bone fractures, through appropriate mounting plates, appropriate functional and aesthetic rehabilitation of the patient were replaced thanks to a temporary removable prosthesis. After 6 months, the patient performed numerous clinical investigations, aimed at a proper planning of implant-prosthetic rehabilitation of the upper dental arch. Conclusion. With the planning of the case, as well as respecting the surrounding biological structures, the surgery of implants can be carried out with the most appropriate procedure. Lastly, new dental implants with highly bioactive surfaces have been developed, providing an excellent and rapid bone integration.

Engineering microdent structures of bone implant surfaces to enhance osteogenic activity in MSCs

Problems persist with the integration of hip and dental implants with host bone tissues, which may result in long-term implant failure. Previous studies have found that implants bearing irregular surfaces can facilitate osseointegration. An improvement to this approach would use implant surfaces harboring a well-defined surface microstructure to decrease variability in implant surfaces. In this study, we tested whether well-defined surfaces with arrays of microdents (each with depth approximately 3 µm) significantly affected the morphology, proliferation, and osteogenic activity of mesenchymal stem cells (MSCs). Arrays of microdents tested had diameters of 9 µm, 12 µm, and 18 µm, while spacing between arrays ranged from 8 µm to 34 µm. Effects on MSC morphology (cell spreading area) and proliferation were also quantified, with both significantly decreasing on micropatterned surfaces (p<0.05) on smaller and denser microdents. In contrast, MSCs were found to deposit more calcified matrix on smaller and denser arrays of microdents. MSCs on a pattern with arrays of microdents with a diameter of 9 µm and a spacing 8 µm deposited 3-4 times more calcified matrix than on a smooth surface (p<0.05). These findings show that well-defined surface microtopographies promote osteogenic activity, which can be used on implant surfaces to improve integration with the host bone tissue.

Early bone formation around immediately loaded implants with nanostructured calcium-incorporated and machined surface: a randomized, controlled histologic and histomorphometric study in the human posterior maxilla

OBJECTIVE

The aim of this randomized, controlled histologic/histomorphometric study was to compare the early bone formation around immediately loaded implants with nanostructured calcium-incorporated (NCI) and machined (MA) surface, placed in the human posterior maxilla.

MATERIALS AND METHODS

Fifteen fully edentulous patients (six males; nine females; mean age 57.9 ± 6.7 years) were selected for this study. Each patient was installed with two temporary transmucosal implants, with different surfaces: one NCI (test) and one MA (control) implant. All temporary implants were placed in the posterior maxilla, according to a split-mouth design, to help to support an interim complete maxillary denture. After 8 weeks, all temporary transmucosal implants were retrieved for histologic/histomorphometric evaluation. The bone-to-implant contact (BIC%) and the bone density (BD%) were calculated. The Wilcoxon matched-pairs signed-rank test was used to evaluate differences (BIC%, BD%) between the surfaces. The level of significance was set at 0.05.

RESULTS

Eight weeks after placement, 24 clinically stable implants (12 test, 12 control) were subjected to histologic/histomorphometric evaluation. In the MA implants, the histomorphometric evaluation revealed a mean BIC(±SD)% and BD(±SD)% of 21.2(±4.9)% and 29.8(±7.8)%, respectively. In the NCI implants, the histomorphometric analysis revealed a mean BIC(±SD)% and BD(±SD)% of 39.7(±8.7)% and 34.6(±7.2)%, respectively. A statistically significant difference was found between the two surfaces with regard to BIC% (p < 0.001), while no significant difference was found with regard to BD% (p = 0.09).

CONCLUSIONS

The NCI surface seems to increase the peri-implant endosseous healing properties in the native bone of the posterior maxilla, under immediate loading conditions, when compared with the MA surface.

CLINICAL RELEVANCE

Under immediate loading conditions in the human posterior maxilla, the nanostructured calcium-incorporated surface has led to better histologic and histomorphometric results than the machined surface; therefore, the clinical use of implants with nanostructured calcium-incorporated surface may be beneficial in the posterior maxilla, under immediate loading protocol.

In Vitro Behavior of Primary Human Osteoblasts Onto Microrough Titanium Surface

OBJECTIVE

The aim of this study was to evaluate in vitro the behavior and the biocompatibility of primary human osteoblasts (HOs) grown onto different implant surface.

METHODS AND MATERIALS

HOs were cultured onto sandblasted/acid-etched (control group) and sandblasted/acid-etched followed by coating with inorganic ions (test group) experimental titanium discs. At established times, SEM analysis, LDH assay, MTT assay, and enzyme-linked immunosorbent assay for type 1 collagen, interleukin (IL)-6, and PGE2 secretion were performed.

RESULTS

Both surfaces promote HOs adhesion and proliferation. After 21 days, cells on test surfaces are well spread, flattened, and attached by cellular extensions, whereas cells on control discs appear mainly elongated. Lower LDH levels and higher values of MTT assay are recorded for cells on test respect to control surfaces at each experimental time. Type 1 collagen release increases until 14 days, significantly decreasing at day 21 in cells grown on both surfaces. IL-6 and PGE2 secretion shows a peak in control group samples at day 7, whereas their levels do not significantly modify in both groups at days 14 and 21.

CONCLUSION

Results indicate that the test group surface is more biocompatible, well tolerated, and suitable for supporting osteoblasts growth and proliferation.

3D Printing/Additive Manufacturing Single Titanium Dental Implants: A Prospective Multicenter Study with 3 Years of Follow-Up

This prospective 3-year follow-up clinical study evaluated the survival and success rates of 3DP/AM titanium dental implants to support single implant-supported restorations. After 3 years of loading, clinical, radiographic, and prosthetic parameters were assessed; the implant survival and the implant-crown success were evaluated. Eighty-two patients (44 males, 38 females; age range 26–67 years) were enrolled in the present study. A total of 110 3DP/AM titanium dental implants (65 maxilla, 45 mandible) were installed: 75 in healed alveolar ridges and 35 in postextraction sockets. The prosthetic restorations included 110 single crowns (SCs). After 3 years of loading, six implants failed, for an overall implant survival rate of 94.5%; among the 104 surviving implant-supported restorations, 6 showed complications and were therefore considered unsuccessful, for an implant-crown success of 94.3%. The mean distance between the implant shoulder and the first visible bone-implant contact was 0.75 mm (±0.32) and 0.89 (±0.45) after 1 and 3 years of loading, respectively. 3DP/AM titanium dental implants seem to represent a successful clinical option for the rehabilitation of single-tooth gaps in both jaws, at least until 3-year period. Further, long-term clinical studies are needed to confirm the present results.

Aesthetic outcome of immediately restored single implants placed in extraction sockets and healed sites of the anterior maxilla: a retrospective study on 103 patients with 3 years of follow-up

OBJECTIVES

The aim of this study was to compare the aesthetic outcome of single implants in extraction sockets and healed ridges of the anterior maxilla by means of the pink aesthetic score/white aesthetic score (PES/WES) index.

MATERIALS AND METHODS

This retrospective study was based on data from 103 patients (43 males, 60 females) aged 24-65 years (mean age 41.4 ± 13.8 years) who had been successfully treated with a single implant in the anterior maxilla, in four different clinical centres. Forty-two patients (mean age 46.5 ± 15.1 years) were treated with a single implant in a fresh post-extraction socket (immediate implant treatment, IIT), while 61 patients (mean age 38.0 ± 11.8 years) were treated with a single implant in a healed site (conventional implant treatment, CIT). Two independent calibrated examiners applied the PES/WES index to the 103 single-tooth restorations, respectively 3 months and 3 years after implant placement.

RESULTS

A few biological (4.8%) and prosthetic (8.7%) complications were reported. Both IIT and CIT yielded satisfactory aesthetic outcomes. At the delivery of the final restoration, a PES/WES score of 16.6 ± 2.6 and 15.7 ± 3.0 was reported for IIT and CIT, respectively: this difference was not statistically significant. A higher decrease in the PES/WES score was observed with CIT over time. At 3 years, a PES/WES score of 16.4 ± 2.8 and 15.2 ± 3.3 was reported for IIT and CIT, respectively: this difference was statistically significant. IIT seemed to yield better aesthetic outcomes in young patients (≤30 years), with implants placed in central incisor/cuspid areas, in the presence of bone contouring.

CONCLUSIONS

Both immediate and conventional single-implant treatment in the anterior maxilla can yield satisfactory aesthetic outcomes, when performed by experienced clinicians in well-selected cases. Further studies are needed to confirm these results.

Maxillary overdentures supported by four splinted direct metal laser sintering implants: a 3-year prospective clinical study

Purpose. Nowadays, the advancements in direct metal laser sintering (DMLS) technology allow the fabrication of titanium dental implants. The aim of this study was to evaluate implant survival, complications, and peri-implant marginal bone loss of DMLS implants used to support bar-retained maxillary overdentures. Materials and Methods. Over a 2-year period, 120 implants were placed in the maxilla of 30 patients (18 males, 12 females) to support bar-retained maxillary overdentures (ODs). Each OD was supported by 4 implants splinted by a rigid cobalt-chrome bar. At each annual follow-up session, clinical and radiographic parameters were assessed. The outcome measures were implant failure, biological and prosthetic complications, and peri-implant marginal bone loss (distance between the implant shoulder and the first visible bone-to-implant contact, DIB). Results. The 3-year implant survival rate was 97.4% (implant-based) and 92.9% (patient-based). Three implants failed. The incidence of biological complication was 3.5% (implant-based) and 7.1% (patient-based). The incidence of prosthetic complication was 17.8% (patient-based). No detrimental effects on marginal bone level were evidenced. Conclusions. The use of 4 DMLS titanium implants to support bar-retained maxillary ODs seems to represent a safe and successful procedure. Long-term clinical studies on a larger sample of patients are needed to confirm these results.

Direct metal laser sintering titanium dental implants: a review of the current literature

Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs); to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS) was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed.

Implant success remains high despite grafting voids in the maxillary sinus

OBJECTIVES

Given that the nature and presence of voids present within grafted sinuses following maxillary sinus elevation procedures were not known, nor was the contribution of these factors to implant success, the purpose of this study was to investigate these parameters and their relationship to implant success.

MATERIALS AND METHODS

This study evaluated data from 25 subjects who had a lateral window maxillary sinus augmentation procedure. Cone-beam computed tomography (CBCT) was performed at baseline and 4 months after surgery. CBCT images were used to evaluate grafted sites prior to implant placement. Using CBCT images, three examiners independently measured bone-grafted areas (BG), void areas (V), and percentage of void areas (V%) from six different sections within grafted sites. The six sections were defined as a cross-sectional (CS) midpoint, CS mesial point, CS distal point, horizontal section (HS) low point, HS midpoint, and HS high point. Implant success was also determined.

RESULTS

The calculated V% (V/BG) for the CS midpoint, CS mesial point, CS distal point, HS low point, HS midpoint, and HS high point were 5.30 ± 6.67%, 5.79 ± 8.51%, 6.67 ± 7.12%, 2.07 ± 2.56%, 5.30 ± 6.62%, and 4.92 ± 5.17% respectively. Implant success after 6 months of follow-up approximated 100%.

CONCLUSIONS

Although voids within grafts varied in terms of distribution and size, the V% within the HS low point were significantly smaller compared to those within the CS midpoint and CS distal point, which had the most intra-subject V%. Thus, more attention should be given to the distal aspect of the sinus when compacting graft materials in the lateral wall sinus augmentation procedure. Implant success was not influenced by the existence of voids as implant success remained high.

Role of primary stability for successful osseointegration of dental implants: Factors of influence and evaluation

A secure implant primary (mechanical) stability is positively associated with a successful implant integration and long-term successful clinical outcome. Therefore, it is essential to assess the initial stability at different time-points to ensure a successful osseointegration. The present study critically reviews the factors that may play a role in achieving a successful initial stability in dental implants. Databases were searched from 1983 up to and including October 2013 using different combinations of various keywords. Bone quality and quantity, implant geometry, and surgical technique adopted may significantly influence primary stability and overall success rate of dental implants.