Prospective clinical evaluation of 201 direct laser metal forming implants: results from a 1-year multicenter study

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.

Forged to heal: The role of metallic cellular solids in bone tissue engineering

Metallic cellular solids, made of biocompatible alloys like titanium, stainless steel, or cobalt-chromium, have gained attention for their mechanical strength, reliability, and biocompatibility. These three-dimensional structures provide support and aid tissue regeneration in orthopedic implants, cardiovascular stents, and other tissue engineering cellular solids. The design and material chemistry of metallic cellular solids play crucial roles in their performance: factors such as porosity, pore size, and surface roughness influence nutrient transport, cell attachment, and mechanical stability, while their microstructure imparts strength, durability and flexibility. Various techniques, including additive manufacturing and conventional fabrication methods, are utilized for producing metallic biomedical cellular solids, each offering distinct advantages and drawbacks that must be considered for optimal design and manufacturing. The combination of mechanical properties and biocompatibility makes metallic cellular solids superior to their ceramic and polymeric counterparts in most load bearing applications, in particular under cyclic fatigue conditions, and more in general in application that require long term reliability. Although challenges remain, such as reducing the production times and the associated costs or increasing the array of available materials, metallic cellular solids showed excellent long-term reliability, with high survival rates even in long term follow-ups.

Additive manufacturing technologies in the oral implant clinic: A review of current applications and progress

Additive manufacturing (AM) technologies can enable the direct fabrication of customized physical objects with complex shapes, based on computer-aided design models. This technology is changing the digital manufacturing industry and has become a subject of considerable interest in digital implant dentistry. Personalized dentistry implant treatments for individual patients can be achieved through Additive manufacturing. Herein, we review the applications of Additive manufacturing technologies in oral implantology, including implant surgery, and implant and restoration products, such as surgical guides for implantation, custom titanium meshes for bone augmentation, personalized or non-personalized dental implants, custom trays, implant casts, and implant-support frameworks, among others. In addition, this review also focuses on Additive manufacturing technologies commonly used in oral implantology. Stereolithography, digital light processing, and fused deposition modeling are often used to construct surgical guides and implant casts, whereas direct metal laser sintering, selective laser melting, and electron beam melting can be applied to fabricate dental implants, personalized titanium meshes, and denture frameworks. Moreover, it is sometimes required to combine Additive manufacturing technology with milling and other cutting and finishing techniques to ensure that the product is suitable for its final application.

Reliability of a Virtual Prosthodontic Project Realized through a 2D and 3D Photographic Acquisition: An Experimental Study on the Accuracy of Different Digital Systems

AIMS

The study aims to assess the accuracy of digital planning in dentistry, evaluating the characteristics of different intraoral 3D scanners and comparing it with traditional imaging 2D recording methods. Specifically, using computer aided design (CAD) software and measuring inside CAD software, authors want to verify the reliability of different models obtained with different techniques and machines.

METHODS

12 patients that needed aesthetic restorative treatment were enrolled in the study. All the patients underwent recording data of the height and width dental elements 1.1, 1.2, and 1.3 size using different technologies and comparing 2D with 3D methods. A T test was then applied in order to verify whether there was a statistically significant difference between the measurements obtained, comparing the different tools data (Emerald, TRIOS, Photogrammetry and DSS (Digital Smile System)) with the reference values.

RESULTS

No significant differences emerged in the measurements made with the different scanners (Trios 3Shape ®, Planmeca Emerald ®) and photogrammetry. Therefore, what should be underlined regarding the 2D measurements is the speed and simplicity compared to all 3D techniques, so this work can help to better define the field of application and the limits connected to 2D techniques, giving a good window of the technique.

CONCLUSIONS

The low number of patients is not sufficient to provide statistically significant results, but the digital planning future prospects seem to be promising. This study results highlighted how a photogrammetric scanner for dental arches would only have a much smaller shooting field size and greater accuracy. Despite these considerations, the photogrammetric facial scanner provided excellent results for the measurement of individual teeth, showing a great versatility of use.

Dental Implants With a Platform-Switched Morse Taper Connection and an Osteo Growth Induction Surface

AIM

The aim of this study was to analyze the clinical outcomes after using an innovative implant system characterized by a modern platform-switched Morse taper connection and an osteo growth induction titanium surface (a particular type of SLA surface). Peri-implant bone loss (PBL) and implant success rate were examined after a 1- to 3-year follow-up.

METHODS

The study was conducted as a cross-sectional analysis on all patients treated from January 2011 to December 2014 using CLC CONIC implants. Implants were divided into 3 main groups, based on the duration of the follow-up (1 year, 2 years, and 3 years), then subgrouped by diameter, length, and type of prosthetic rehabilitation to compare differences in PBL. X-rays were taken at the time of surgery, at prosthetic loading, at 1 year, and then annually thereafter. Previously-established success criteria were used to assess the implants. Frequency analyses and comparisons between the means (with 95% CI) were conducted for the statistical analysis of the data collected.

RESULTS

One hundred twenty patients met inclusion and exclusion criteria, and completed the follow-up, and were thus eligible for the study, with a total of 261 CLC CONIC implants. The mean follow-up was 22.45 months. No implants failed, giving an overall success rate of 100%. The average PBL at 1-year follow-up was 0.047 mm, at 2 years it was 0.128 mm, and at 3 years it was 0.236 mm.

CONCLUSIONS

The CLC CONIC implant system had a high success rate after 1 to 3 years of follow-up, in line with previous reports in the scientific literature. Combining platform switching with the Morse taper connection enabled stable bone levels to be achieved in the short to medium term.

Custom-Made Direct Metal Laser Sintering Titanium Subperiosteal Implants: A Retrospective Clinical Study on 70 Patients

Purpose

To present a digital technique for the fabrication of custom-made subperiosteal implants and to report on the survival and complication rates encountered when using these fixtures.

Methods

The data used for this retrospective clinical study were derived from the medical records of five different private dental practices. Inclusion criteria were patients over the age of 60, treated with custom-made direct metal laser sintering (DMLS) titanium subperiosteal implants (Eagle-Grid®, BTK, Dueville, Vicenza) during a two-year period (2014-2015) and restored with fixed restorations; all enrolled patients needed to have complete pre- and postoperative clinical and radiographic documentation, with at least 2 years of follow-up. Exclusion criteria were smoking and bruxism. The main outcomes looked at were implant survival and complications.

Results

Seventy patients (39 males and 31 females, aged 62-79 years) who had been treated with custom-made DMLS titanium subperiosteal implants were enrolled in this study. After 2 years of follow-up, three implants were lost due to recurrent, untreatable infections; the survival rate was therefore 95.8% (67/70 implants). Four patients reported pain/discomfort/swelling after implant placement; the incidence of immediate postoperative complications was therefore 5.7% (4/70 implants). During the follow-up period, one patient suffered from recurrent infections classified as a biologic complication; the incidence of biologic complications was therefore 1.4% (1/67 surviving implants). Finally, four patients experienced prosthetic problems with their implant-supported restorations during the provisional phase (fracture of the acrylic restoration) and two patients had ceramic chipping of the definitive restoration; the incidence of prosthetic complications was therefore 8.9% (6/67 surviving implants).

Conclusions

Within the limits of the present study (limited follow-up time and low number of patients treated, retrospective design), the application of custom-made DMLS titanium subperiosteal implants showed satisfactory implant survival (95.8%) and low complication rates. Further studies are needed to confirm the positive outcomes found in this research.

The Influence of Electrolytic Concentration on the Electrochemical Deposition of Calcium Phosphate Coating on a Direct Laser Metal Forming Surface

A calcium phosphate (CaP) coating on titanium surface enhances its biocompatibility, thus facilitating osteoconduction and osteoinduction with the inorganic phase of the human bone. Electrochemical deposition has been suggested as an effective means of fabricating CaP coatings on porous surface. The purpose of this study was to develop CaP coatings on a direct laser metal forming implant using electrochemical deposition and to investigate the effect of electrolytic concentration on the coating's morphology and structure by X-ray diffraction, scanning electron microscopy, water contact angle analysis, and Fourier transform infrared spectroscopy. In group 10-2, coatings were rich in dicalcium phosphate, characterized to be thick, layered, and disordered plates. In contrast, in groups 10-3 and 10-4, the relatively thin and well-ordered coatings predominantly consisted of granular hydroxyapatite. Further, the hydrophilicity and cell affinity were improved as electrolytic concentration increased. In particular, the cells cultured in group 10-3 appeared to have spindle morphology with thick pseudopodia on CaP coatings; these spindles and pseudopodia strongly adhered to the rough and porous surface. By analyzing and evaluating the surface properties, we provided further knowledge on the electrolytic concentration effect, which will be critical for improving CaP coated Ti implants in the future.

Patient specific root-analogue dental implants – additive manufacturing and finite element analysis

Aim of this study was to prove the possibility of manufacturing patient specific root analogue two-part (implant and abutment) implants by direct metal laser sintering. The two-part implant design enables covered healing of the implant. Therefore, CT-scans of three patients are used for reverse engineering of the implants, abutments and crowns. Patient specific implants are manufactured and measured concerning dimensional accuracy and surface roughness. Impacts of occlusal forces are simulated via FEA and compared to those of standard implants.

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.

Preoperative Planning of Virtual Osteotomies Followed by Fabrication of Patient Specific Reconstruction Plate for Secondary Correction and Fixation of Displaced Bilateral Mandibular Body Fracture

This paper describes the course of treatment of a severely diplaced bilateral mandibular body fracture, where the first osteosynthesis failed. The subject developed an open bite due to a posterior rotation of the distal part of the mandible and anterior rotation of the proximal parts of the mandible. This situation was evaluated with CBCT and the facial skeleton was segmented using computer software. Correct occlusion was virtually established by bilateral virtual osteotomies in the fracture areas of the mandible. After segmentation, the mandible was virtually rotated back into position and the open bite was closed. A patient specific mandibular reconstruction plate was outlined and fabricated from the new virtual situation and the plate was thereafter installed utilizing the preoperative plan. Osteotomy- and drill-guides was used and thus simplified the surgery resulting in uneventful healing. Virtual planning and patient specific implants and guides were valuable in this case of secondary reconstructive trauma surgery.

Surface characterization and in vivo evaluation of laser sintered and machined implants followed by resorbable-blasting media process: A study in sheep

Background

This study aimed to compare the histomorphometric and histological bone response to laser-sintered implants followed by resorbable-blasting media (RBM) process relative to standard machined/RBM surface treated implants.

Material and Methods

Six male sheep (n=6) received 2 Ti-6Al-4V implants (1 per surface) in each side of the mandible for 6 weeks in vivo. The histomorphometric parameters bone-implant contact (BIC) and bone area fraction occupancy (BAFO) were evaluated.

Results

Optical interferometry revealed higher Sa and Sq values for the laser-sintered/RBM surface in relation to standard/RBM implants. No significant differences in BIC were observed between the two groups (p>0.2), but significantly higher BAFO was observed for standard/RBM implants (p<0.01).

Conclusions

The present study demonstrated that both surfaces were biocompatible and osseoconductive, and the combination of laser sintering and RBM has no advantage over the standard machined implants with subsequent RBM.

Key words:Dental implants, osseointegration, resorbable- blasting media, sheep, in vivo.

Microscopic view of osseointegration and functional mechanisms of implant surfaces

Argon ion beam polishing technique was applied to prepare the cross sections of implants feasible for high resolution scanning electron microscope investigation. The interfacial microstructure between newly formed bone and implants with three modified surfaces retrieved after in vivo test using three different animal models was characterized. By this approach it has become possible to directly observe early bone formation, the increase of bone density, and the evolution of bone structure. The two bone growth mechanisms, distant osteogenesis and contact osteogenesis, can also be distinguished. These direct observations give, at microscopic level, a better view of osseointegration and expound the functional mechanisms of various implant surfaces for osseointegration.

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.

Effects of different abutment material and surgical insertion torque on the marginal adaptation of an internal conical interface: an in vitro study

PURPOSE

To evaluate the marginal adaptation at implant-abutment connection of an implant featuring a conical (45° taper) internal hexagonal abutment with a connection depth of 2.5mm, comparing the performance of two identical abutments of different material (titanium grade-4 and Co-Cr-alloy).

METHODS

Twenty implants (3.75 mm×15 mm) were connected to non-matching abutments (5.5 mm×10 mm) of two different materials (titanium grade-4: n=10; Co-Cr-alloy: n=10). The specimens were separately embedded in epoxylite resin, inside copper cylinders, and submerged without covering the most coronal portion (5 mm) of the fixture. Five specimens per group were stressed simulating a surgical 100 Ncm insertion torque, while the others had no torque simulation. All specimens were subjected to a non-axial static load (100 N) in a universal testing machine, under an angle of 30° with respect to the implant axis. Once 100 N load was reached, low shrinkage self-curing resin was injected inside the cylinders, and load was maintained until complete resin polymerization. Specimens were cut and analyzed with optical and scanning-electron-microscope (SEM) to evaluate the marginal adaptation at the implant-abutment connection. Statistical analysis was performed using one-way ANOVA (p=0.02).

RESULTS

None of the 20 samples failed. The implant-abutment connection was able to guarantee a good optical seal; SEM analysis confirmed the absence of microgaps.

CONCLUSIONS

Within the limits of this study (small sample size, limited time) the marginal adaptation of the implant-abutment connection was not affected by the abutment material nor by the application of surgical insertion torque.

Reasons for failures of oral implants

This study reviews the literature regarding the factors contributing to failures of dental implants. An electronic search was undertaken including papers from 2004 onwards. The titles and abstracts from these results were read to identify studies within the selection criteria. All reference lists of the selected studies were then hand-searched, this time without time restrictions. A narrative review discussed some findings from the first two parts where separate data from non-comparative studies may have indicated conclusions different from those possible to draw in the systematic analysis. It may be suggested that the following situations are correlated to increase the implant failure rate: a low insertion torque of implants that are planned to be immediately or early loaded, inexperienced surgeons inserting the implants, implant insertion in the maxilla, implant insertion in the posterior region of the jaws, implants in heavy smokers, implant insertion in bone qualities type III and IV, implant insertion in places with small bone volumes, use of shorter length implants, greater number of implants placed per patient, lack of initial implant stability, use of cylindrical (non-threaded) implants and prosthetic rehabilitation with implant-supported overdentures. Moreover, it may be suggested that the following situations may be correlated with an increase in the implant failure rate: use of the non-submerged technique, immediate loading, implant insertion in fresh extraction sockets, smaller diameter implants. Some recently published studies suggest that modern, moderately rough implants may present with similar results irrespective if placed in maxillas, in smoking patients or using only short implants.

Immediate, non-submerged, root-analogue direct laser metal sintering (DLMS) implants: a 1-year prospective study on 15 patients

This study evaluated the 1-year survival and success rate of root-analogue direct laser metal sintering (DLMS) implants, placed into the extraction sockets of 15 patients. DLMS is a technology which allows solids with complex geometry to be fabricated by annealing metal powder microparticles in a focused laser beam, according to a computer-generated three-dimensional (3D) model; the fabrication process involves the laser-induced fusion of titanium microparticles, in order to build, layer-by-layer, the desired object. Cone-beam computed tomography (CBCT) acquisition and 3D image conversion, combined with the DLMS process, allow the fabrication of custom-made, root-analogue implants (RAIs). CBCT images of 15 non-restorable premolars (eight maxilla; seven mandible) were acquired and transformed into 3D models: from these, custom-made, root-analogue DLMS implants with integral abutment were fabricated. Immediately after tooth extraction, the RAIs were placed in the sockets and restored with a single crown. One year after implant placement, clinical and radiographic parameters were assessed: success criteria included absence of pain, suppuration, and exudation; absence of implant mobility and absence of continuous peri-implant radiolucency; distance between the implant shoulder and the first visible bone-to-implant contact <1.5 mm from initial surgery; and absence of prosthetic complications. At the 1-year follow-up, no implants were lost, for a survival rate of 100 %. All implants were stable, with no signs of infection. The good conditions of the peri-implant tissues were confirmed by the radiographic examination, with a mean DIB of 0.7 mm (±0.2). The possibility of fabricating custom-made, RAI DLMS implants opens new interesting horizons for immediate placement of dental implants.

Custom-made, selective laser sintering (SLS) blade implants as a non-conventional solution for the prosthetic rehabilitation of extremely atrophied posterior mandible

The treatment of severely atrophied posterior mandibles with standard-diameter root-form implants may present a challenge. Bone reconstructive surgery represents the treatment of choice; however, it may not be accepted by some patients for economic reasons or due to higher morbidity. Computer-aided design/computer-aided manufacturing (CAD/CAM) technologies have recently opened new frontiers in biomedical applications. Selective laser sintering (SLS) is a CAD/CAM technique that allows the fabrication of complex three-dimensional (3D) structures created by computer-generated image-based design techniques. The aim of this study is to present a protocol for the manufacture and clinical use of custom-made SLS titanium blade implants as a non-conventional therapeutic treatment for the prosthetic rehabilitation of extremely atrophied posterior mandibles. Computed tomography datasets of five patients were transferred to a specific reconstruction software, where a 3D projection of the atrophied mandible was obtained, and custom-made endosseous blade implants were designed. The custom-made implants were fabricated with SLS technique, placed in the extremely atrophied posterior (<4 mm width) mandible, and immediately restored with fixed partial restorations. After 2 years of loading, all implants were in function, showing a good esthetic integration. Blade implants can be fabricated on an individual basis as a custom-designed device. This non-conventional approach may represent an option for restoring the atrophied posterior mandible of elderly patients.

Maxillary sinus augmentation using computer-aided design/computer-aided manufacturing (CAD/CAM) technology

BACKGROUND

Maxillary sinus augmentation is a common method for increasing bone height for insertion of dental implants. In most cases, the graft is manually cut into a roughly appropriate shape by visual estimation during the operation; accordingly, the shape of the graft depends considerably on the experience of the surgeon. We have developed a computer-aided design/computer-aided manufacturing (CAD/CAM) technique to generate custom-made block grafts for sinus augmentation, and a customized cutting guide to precisely position the lateral wall and facilitate membrane elevation, using cone-beam computed tomography (CBCT).

METHODS

Custom-made blocks of hydroxyapatite (HA) were preoperatively cut to the required shape, based on a three-dimensional (3D) simulation, using CAD/CAM technology. The custom-made HA blocks were used for sinus augmentation.

RESULTS

Five patients underwent bilateral sinus elevation with custom-made HA blocks. Six months later, implants were placed. Two years after placement, all implants were in function. No clinical or prosthetic complications were encountered.

CONCLUSIONS

We present a CAD/CAM technique for the fabrication of custom-made block grafts for sinus augmentation.

Reliability evaluation of alumina-blasted/acid-etched versus laser-sintered dental implants

Step-stress accelerated life testing (SSALT) and fractographic analysis were performed to evaluate the reliability and failure modes of dental implant fabricated by machining (surface treated with alumina blasting/acid etching) or laser sintering for anterior single-unit replacements. Forty-two dental implants (3.75 × 10 mm) were divided in two groups (n=21 each): laser sintered (LS) and alumina blasting/acid etching (AB/AE). The abutments were screwed to the implants and standardized maxillary central incisor metallic crowns were cemented and subjected to SSALT in water. Use-level probability Weibull curves and reliability for a mission of 50,000 cycles at 200 N were calculated. Polarized light and scanning electron microscopes were used for failure analyses. The Beta (β) value derived from use-level probability Weibull calculation of 1.48 for group AB/AE indicated that damage accumulation likely was an accelerating factor, whereas the β of 0.78 for group LS indicated that load alone likely dictated the failure mechanism for this group, and that fatigue damage did not appear to accumulate. The reliability was not significantly different (p>0.9) between AB/AE (61 %) and LS (62 %). Fracture of the abutment and fixation screw was the chief failure mode. No implant fractures were observed. No differences in reliability and fracture mode were observed between LS and AB/AE implants used for anterior single-unit crowns.

Custom-made, root-analogue direct laser metal forming implant: a case report

In the last few years, the application of digital technology in dentistry has become widespread with the introduction of cone beam computed tomography (CBCT) scan technology, and considerable progress has been made in the development of computer-aided design/ computer-aided manufacturing (CAD/CAM) techniques, including direct laser metal forming (DLMF). DLMF is a technology which allows solids with complex geometry to be produced by annealing metal powder microparticles in a focused laser beam, according to a computer-generated three-dimensional (3D) model. For dental implants, the fabrication process involves the laser-induced fusion of titanium microparticles, in order to build, layer by layer, the desired object. At present, the combined use of CBCT 3D data and CAD/CAM technology makes it possible to manufacture custom-made, root-analogue implants (RAI) with sufficient precision. This report demonstrates the successful clinical use of a custom-made, root-analogue DLMF implant. CBCT images of a non-restorable right maxillary first premolar were acquired and transformed into a 3D model. From this model, a custom-made, root-analogue DLMF implant was fabricated. Immediately after tooth extraction, the RAI with a pre-operatively designed abutment was placed in the extraction socket and restored with a single crown. At the 1-year follow-up examination, the RAI showed a good functional and aesthetic integration. The introduction of DLMF technology signals the start of a new revolutionary era for implant dentistry as its immense potential for producing highly complex macro- and microstructures is receiving vast interest in different medical fields.

Characterization and in vivo evaluation of laser sintered dental endosseous implants in dogs

Laser metal sintering has shown promising results, but no comparison with other commercially available surface has been performed. This study sought to evaluate the biomechanical and histological early bone response to laser sintered implants relative to alumina-blasted/acid-etched (AB/AE). Surface topography was characterized by scanning electron microscopy and optical interferometry. Surface chemistry was assessed by x-ray photoelectron spectroscopy. Beagle dogs (n = 18) received 4 Ti-6Al-4V implants (one per surface) in each radius, remaining for 1, 3, and 6 weeks (n = 6 dogs per evaluation time) in vivo. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were evaluated. Biomechanical evaluation comprised torque-to-interface failure. The laser sintered surface presented higher S(a) and S(q) than AB/AE. Chemistry assessment showed the alloy metallic components along with adsorbed carbon species. Significantly higher torque was observed at 1 (p < 0.02) and 6 week (p < 0.02) for the laser sintered, whereas at 3 week no significant differences were observed. Significantly higher BIC and BAFO was observed for the Laser Sintered (p < 0.04, and p < 0.03, respectively) only at 1 week, whereas no significant differences were observed at 3 and 6 weeks. The laser sintered implants presented biocompatible and osseoconductive properties and improved biomechanical response compared with the AB/AE surface only at 1 and 6 weeks in vivo.