Titanium Mini-implants Research Articles

Assessment of Toxicity of Green Synthesized Silver Nanoparticle-coated Titanium Mini-implants with Uncoated Mini-implants: Comparison in an Animal Model Study.

To assess the potential for systemic toxicity when silver nanoparticle-coated mini-implants were implanted in Wistar albino rats conducted as a comparative study in the animal model by assessing the blood biochemistry, liver and kidney function, and histology of the implanted site. The surface of the mini-implant was coated with a green-mediated silver nanoparticle. Uncoated mini-implants were placed in two groups of eight Wistar albino rats, and silver nanoparticle-coated mini-implants were placed in another eight rats. The bone's general conditions, blood biochemistry assessing for ALT, AST, GPT, GOT, and histological sections using H and E stain and Masson's Trichrome stain were examined at 7, 14, and 28-day intervals. The creatinine, urea, ALP, and ALT showed no signs of systemic toxicity during the 28-day follow-up period in the Wistar rats both in the test and control groups. The histological evaluation, which was conducted using HE and MTS stain, revealed osteogenesis and adequate healing of the insertion site in the group where coated mini-implant was placed. The bone sample revealed no abnormalities in the control group with uncoated mini-implants. Green synthesized silver nanoparticle-coated mini-implant does not cause systemic toxicity as indicated by no abnormalities in the levels of creatinine, urea, ALT, ALP, GPT, and GOT. The bone histology indicates that the coated mini-implants placed in animal bone healed with adequate osteogenesis. Silver nanoparticles have potential for antimicrobial activity. Mini-implants placed as temporary anchorage devices in orthodontics often fail due to inflammation and plaque. Silver nanoparticle-coated mini-implants would reduce the risk of mini-implant failure as it would have antimicrobial potential and eliminate this cause for failure of mini-implants. How to cite this article: Sreenivasagan S, Subramanian AK, Mohanraj KG, et al. Assessment of Toxicity of Green Synthesized Silver Nanoparticle-coated Titanium Mini-implants with Uncoated Mini-implants: Comparison in an Animal Model Study. J Contemp Dent Pract 2023;24(12):944-950.

Effect of Fluorides on the Corrosion Properties of Titanium Mini-implants: A Systematic Review

Objective: This systematic review plans to evaluate the effects of fluoride ions on the corrosion properties of titanium mini-implants. Background: Mini-implants are broadly used in orthodontics as an alternative to traditional intraoral anchorage. They comprise of Ti-6Al-4V with a passive oxide film of titanium dioxide for high corrosion resistance properties. To maintain oral hygiene orthodontic patients are often prescribed fluoride mouth rinses, toothpastes, etc, which might affect the corrosion resistance properties of mini-implants. Materials and methods: A literature search by means of proper MeSH terms and PICO format was done using the following databases: Google Scholar, PubMed, and EBSCO HOST. The following studies will be included- Randomized Controlled Trials, Observational studies, In-vivo studies, In-vitro studies, Clinical studies, and Human studies on the corrosion of titanium mini-implants subjected to fluorides. Exclusion criteria included surveys and questionnaire-based studies, review letters, personal opinions, book chapters, and conference abstracts. Results: A total of 134 articles were obtained, and 5 were selected for inclusion in the review. Results showed that fluoride ions significantly dropped the corrosion resistance properties of titanium. Conclusion: The acidic environment due to low pH and increase in the fluoride ion concentration seems to directly affect the corrosion resistance properties of titanium mini-implants, and attention must be paid while prescribing fluoride agents when titanium mini-screws are used.

Clinical evaluation and assessment of laser irradiation on the stability of orthodontic implant - A prospective experimental study

ABSTRACT Background: Currently, orthodontic implants have reached a peak where they are considered a dependable modality to provide temporary supplemental anchoring in orthodontic therapy. When absolute anchoring is a necessity or in cases of minimally cooperative patients, these devices can help manage skeletal anchorage. However, its failure is a serious multi-factorial issue that happens during orthodontic treatment. The stability of the mini-implant is crucial to the outcome of orthodontic intervention. Approaches to increasing the stability of the mini-implant were researched. Hence, this study was carried out to compare and contrast and clinically assess the integrity of orthodontic implants over time. Subjects and Methods: Split mouth technique of treatment was carried out on 16 patients, i.e., one side of the mandible was considered as the experimental group (implant site irradiated with laser after placement), and the other was considered as the control side (implant site not irradiated with laser). Titanium mini-implants of the dimensions 1.5 mm diameter and 6 mm length were employed in the present study. They were positioned in the inter radicular space between the first molar and second premolar in the mandibular posterior region, 7 mm apical to the alveolar crest. During the whole process, the laser utilized was a multimode GaAs diode laser with a wavelength of 980 nm. It had 0.5–10 W output power which was adjustable with the frequency of 1–20 kHz and its main body input voltage was DC12 to further analyze the stability of the implant which in turn would aid in success assessment, the resonance frequency concept was utilized. The readings were recorded (T0) after insertion, (T1) 24 h after insertion, (T2) 2 weeks after insertion, (T3) 4 weeks after insertion, (T4) 6 weeks after insertion, and (T5) 8 weeks after insertion. The higher the implant stability quotient values the greater the stability and hence the optimal loading time. Results: The test employed for statistical analysis was Mann–Whitney U, Kruskal Wallis, and analysis of variance test. After analysis of all the readings, it was found that low-level laser therapy has a significant role in the stability of orthodontic mini-implant. Conclusion: The findings from this study suggest that low-level laser irradiation at the time of implant placement controls the inflammatory reaction around the implant and improves its stability.

Bacteriostatic Poly Ethylene Glycol Plasma Coatings for Orthodontic Titanium Mini-Implants.

Titanium mini-implants are used as anchorage for orthodontic tooth movements. However, these implants present problems due to the infection of surrounding tissues. The aim of this work was to obtain a polyethylene glycol (PEG) layer by plasma in order to achieve a bacteriostatic surface. Titanium surfaces were activated by argon plasma and, after, by PEG plasma with different powers (100, 150 and 200 W) for 30 and 60 min. The roughness was determined by white light interferometer microscopy and the wettability was determined by the contact angle technique. Surface chemical compositions were characterized by X-ray photoelectron spectroscopy (XPS) and cytocompatibility and cell adhesion studies were performed with fibroblast (hFFs) and osteoblast (SAOS-2) cells. Bacterial cultures with Spectrococcus Sanguinis and Lactobacillus Salivarius were performed, and bacterial colonization was determined. The results showed that plasma treatments do not affect the roughness. Plasma makes the surfaces more hydrophilic by decreasing the contact angles from 64.2° for titanium to 5.2° for argon-activated titanium, with values ranging from 12° to 25° for the different PEG treatments. The plasma has two effects: the cleaning of the surface and the formation of the PEG layer. The biocompatibility results were, for all cases, higher than 80%. The polymerization treatment with PEG reduced the adhesion of hFFs from 7000 to 6000 and, for SAOS-2, from 14,000 to 6500, for pure titanium and those treated with PEG, respectively. Bacterial adhesion was also reduced from 600 to 300 CFU/mm2 for Spetrococcuns Sanguinis and from 10,000 to 900 CFU/mm2 for Lactobacillus Salivarius. The best bacteriostatic treatment corresponded to PEG at 100 W and 30 s. As a consequence, the PEG coating would significantly prevent the formation of bacterial biofilm on the surface of titanium mini-implants.

Efficacy of Infrazygomatic Crest Implants for Full-arch Distalization of Maxilla and Reduction of Gummy Smile in Class II Malocclusion

The purpose of the study was to evaluate the efficacy of infrazygomatic (IZ) implants along with mini-implants for full-arch distalization of maxilla and reduction of gummy smile in patients with class II division I malocclusion. Ten orthodontic patients were taken from the department of orthodontics and dentofacial orthopedics. Each patient required distalization and intrusion of the complete maxillary arch as a part of the treatment plan. Patients were of class II malocclusion with gummy smile. Initial leveling and alignment were done by using 0.22″ slot Mclaughlin Bennett Trevisi (MBT) prescription. Fav Anchor infrazygomatic crest (IZC) implants of 2 mm of head diameter and 14 mm length were inserted between first and second molar and 2 mm above the mucogingival junction in the alveolar mucosa and in the anterior region, two titanium mini-implants of 1.4 mm head diameter and 6 mm length. The screws were loaded immediately with e-chain with a minimal force from mini-implants in the anterior region to crimpable hook placed between lateral and canine and continuing the same till the IZ implants. To measure the amount of distalization and reduction of gummy smile, pre- and postlateral cephalograms were taken and assessed. Pre- and postdistalization and intrusion readings of all patients were obtained and calculated statistically for quantifying the amount of distalization of maxillary arch and intrusion for reduction of gummy smile. The distalization of the maxillary arch achieved was 4.6 mm which is clinically and statistically significant. The anterior teeth in the study were intruded with a minimum of 3.8 mm which is clinically and statistically significant; the gingival smile line was reduced with a mean of 3.4 mm which is clinically and statistically significant. Overbite correction of 4 mm was done with the mean difference of 4 mm which is also statistically significant. The IZ bone screws can be effectively used as an absolute anchorage to correct class II skeletal discrepancy with gummy smile devoid of premolar extraction with noninvasive procedure. The use of IZC implants along with anterior implants, a biomechanical approach is effective in achieving full-arch distalization of maxilla and intrusion as the force vectors allow that the line of action passes through the center of resistance (Cr) of the entire maxillary arch, facilitates the distalization and intrusion of the maxillary arch, establishes ideal occlusion, and improves the smile esthetics.

Effect of metal ions released from orthodontic mini-implants on osteoclastogenesis.

Orthodontic mini-implants can undergo corrosion and the release of metal ions can affect cellular behavior. Osteoclasts are involved in orthodontic tooth movement and implant stability. Osteoclasts and their precursors can be exposed to metal ions released from orthodontic mini-implants. This study aimed to investigate the effect of metal ions released from orthodontic miniimplants on human osteoclastogenesis. Stainless steel and titanium alloy mini-implants were separately immersed in culture media for 14 days (days 1-14), and then moved to new media for a further 14 days (days 15-28). The concentration of the released metal ions was measured. Osteoclast precursors derived from human CD14+ monocytes were cultured in these media and in a control medium without mini-implant immersion. Cell viability, the number of osteoclasts and the area of resorption were investigated. A higher concentration of metal ions was detected during the first 14 days as compared to the control. The concentration of these metal ions then declined after this period. The viability of osteoclast precursors was not affected by the released metal ions. There was a significant reduction in the number of osteoclasts when cultured in the medium with the titanium alloy mini-implants immersed for days 1-14. The area of resorption was also significantly reduced in this group. The media with the titanium alloy mini-implants immersed for days 15-28 and with the stainless steel mini-implants immersed for both study periods did not show statistically significant changes in the number of osteoclasts. Metal ions were released from orthodontic mini-implants in the early period and declined thereafter. Metal ions released from titanium mini-implants in the early period inhibited osteoclastogenesis, while metal ions from stainless steel mini-implants had no effect on osteoclast differentiation.

Do Titanium Mini-Implants Have the Same Quality of Finishing and Degree of Contamination before and after Different Manipulations? An In Vitro Study

Evaluate the quality of finishing and degree of contamination before and after handling and surface treatment of titanium (Ti) orthodontic mini-implants (OMIs). A scanning electron microscope (SEM) study on ninety-six titanium OMIs was done. Energy-Dispersive X-ray Analysis (EDX) identified the present particles on manufactured OMIs surfaces. Then, OMIs were manipulated with gauze (dry sterile, soaked in chlorhexidine) and gloves (latex, nitrile) to evaluate the contamination of these handling materials. Finally, OMIs underwent surface treatments and were placed in bone to observe the contaminants they released. Roughness (Ra) and wettability with contact angle parameter (CA) were measured on these treated OMIs. Machined OMIs presented surface irregularities and were contaminated with manufacturing-process particles (carbon, plastic Polyvinyl Chloride PVC, aluminum). Hand-manipulated OMIs were also contaminated by the handling materials. OMIs surface characteristics were as follows: acid-etched (Ra ≈ 1.3 μm, CA ≈ 66°), machined (Ra ≈ 0.3 μm, CA ≈ 68°), SB (Ra ≈ 3.3 μm, CA ≈ 78°), and SBAO (Ra ≈ 3.1 μm, CA ≈ 92°). Bone was contaminated by OMIs surface defects and extra particles. Manufactured OMIs have surface contaminants that increase with clinical handling. Surface treatments (SBAO, a combination of sandblasting and anodic oxidation) increase the roughness and contact angle, which play an important role in osseointegration. Surface-treated OMIs leave titanium particles in the bone during their insertion-removal. The use of a gauze soaked in chlorhexidine is recommended when handling OMIs. Further investigations would be interesting to study more variables and confirm the present results.

RETENTION OF MINI SCREWS IN ORTHODONTICS – A COMPARATIVE IN VITRO STUDY ON THE VARIABLES

Objectives: To correlate between the different lengths, angles of insertion and the mini-implant material and find out the most retentive combination.
 Materials and methods: 48 mini-implants (24 Titanium and 24 stainless steel) of lengths 6mm, 8mm and 1.5 mm diameter were inserted into humerus bone of goat at two different angulations, 600 and 900. To insert the mini-implant in the respective angulations, custom made template was made and the angles were confirmed with digital radiographs. Force was applied on to the mini-implants with a universal testing machine and the compressive load to failure was measured.
 Results: Results revealed that stability of the implant was positively correlating with the length of implant. A perpendicular angulation produced more stability. Moreover, titanium mini-implants had more resistance to compressive load than stainless steel mini-implants.
 Conclusion: Length of mini-implant, its angulation in the bone and the material of mini-implant were factors affecting its stability. In this study, titanium mini-implant of 8mm length angulated at 900 were stable than their counterparts.

Evaluation and comparison of mechanical properties between commercially available mini-implants: An in vitro study

Objective: The objective of this study is to evaluate the mechanical properties of different commercial brands of mini-implants by subjecting them to loads perpendicular to their long axis. Materials and Methods: A total of 120 mini-implants were divided into six groups (n = 20): Group 1A - 20 stainless steel (SS) mini-implants (SK Orthodontics, India), Group 1B - 20 SS mini-implants (BK Orthodontics, India), Group 1C - 20 SS mini-implants (JSV Surgicals, India), Group 2A - 20 titanium mini-implants (Koden surgical, India), Group 2B - 20 Titanium mini-implants (JSV Orthodontics, India), and Group 2C - 20 titanium mini-implants (Dentos, Korea) were used. The mini-implants were placed perpendicularly into 12 acrylic blocks and were submitted to mechanical tests using a standard universal testing machine (ACME, India. Model no. UNIT TEST-10). The different forces required to fracture mini-implants after undergoing 0.5, 1, 1.5, and 2 mm deformation was assessed. Results: Mini-implants in Group 2C (Titanium Dentos Korea) required the greatest force to deform and fracture, whereas Group 1C (JSV Surgicals, India) had the lowest fracture force. Statistically significant differences were seen when an intragroup comparison was done. Statistically significant differences were seen in the comparison between the SS and titanium groups (P Conclusions: SS mini-implants exhibited a high degree of resistance to deform and fracture, but they were inferior compared with titanium mini-implants. Titanium mini-implants required higher force values to deform and fracture.

Stainless steel or titanium mini-implants?

To investigate whether there was a difference in success rates when stainless steel (SS) was compared to titanium mini-implants (MIs) in orthodontic patients. PubMed, Cochrane, Scopus, Web of Science, Lilacs, Google Scholar, Clinical Trials, and OpenGray were searched without restrictions. A manual search was also performed in the references of the included articles. Studies comparing the success rate between SS and titanium MIs were included. Risk of bias (RoB) was assessed using the ROBINS-I (Risk of Bias in Non-randomized Studies-of Interventions) Tool or RoB 2.0 according to the study design. The level of evidence was assessed through GRADE (Grading of Recommendation, Assessment, Development, and Evaluation). Six studies met the eligibility criteria. One study was a randomized clinical trial that evaluated extraalveolar MIs, and nonrandomized trials examined interradicular MIs. The RCT presented a low RoB, two nonrandomized trials presented a moderate risk, and three presented a high risk. The quality of the evidence was high for the randomized clinical trial and moderate for the nonrandomized trials. Most studies found no difference between materials, with good success rates for both (SS, 74.6%-100%; titanium: 80.9%-100%) and only one study, with a high RoB, showed a higher success rate with titanium MIs (90%) when compared with SS (50%). A quantitative analysis was not because of the great heterogeneity among the studies. Although limited, the current evidence seems to show that the material used is not a major factor in the success rate of MIs. Because it has a lower cost than titanium and presents similar clinical efficiency, SS is a great material for orthodontic MIs.

Bone Healing at Implants Placed in Sites Prepared Either with a Sonic Device or Drills: A Split-Mouth Histomorphometric Randomized Controlled Trial.

To evaluate histomorphometrically early healing at implants placed in sites prepared with either a sonic device or conventional drills. Sixteen volunteer patients were recruited. Two titanium mini-implants were placed in the distal segments of the maxilla in recipient sites prepared with either a sonic device or conventional drills. Biopsy specimens containing the mini-implants were retrieved after 2 weeks in eight patients, and after 6 weeks in the other eight patients. Histomorphometric analyses were performed. Histologic slides were available from seven patients for both 2-week and 6-week periods. After 2 weeks of healing, small amounts of new bone were found in contact with the implant surface, with 5.5% ± 7.3% and 3.8% ± 10.0% at the sonic and drill groups, respectively. After 6 weeks of healing, new bone was 46.9% ± 15.5% at the sonic group, and 46.4% ± 14.9% at the drill group. None of the differences was statistically significant. The percentage of new bone in contact with the implant surface was similar in the sonic and drill groups.

Do Chlorhexidine and Probiotics Solutions Provoke Corrosion of Orthodontic Mini-implants? An In Vitro Study.

The aim of this study was to explore the surface roughness and hardness of the implant head of orthodontic mini-implants made from different alloys before and after their in vitro exposure to agents for prevention of gingivitis, mucositis, and peri-implantitis: chlorhexidine and probiotics. Three types of commercially available mini-implants were tested: 316 stainless steel, titanium Grade 5, and titanium Grade 23 (both Ti-6Al-4V alloys with the same atomic weight percentage of Ti, Al, and V, with the difference being in maximal reduction of O2 in Grade 23 to 0.13% of atomic weight). They were immersed in three experimental solutions: artificial saliva, saliva with probiotic bacteria Lactobacillus reuteri, and saliva with oral antiseptic chlorhexidine (CHX). Samples were immersed for 28 days, thermocycled, then stored in an incubator at 37°C. Surface roughness and microhardness on five samples of each of the three implant types were measured by atomic force microscopy and the Vickers method, respectively. Exposure of titanium implant Grade 5 to probiotics significantly increased roughness compared with other media (P < .005). Exposure to CHX significantly increased the roughness of steel implants (P < .05). Neither saliva, probiotic, nor CHX altered microhardness of titanium implants significantly. In steel implants, the exposure to CHX and probiotics decreased microhardness compared with unexposed implants (P < .031), but not in comparison to saliva. Probiotics seem to increase roughness of titanium mini-implants, while CHX seems to increase roughness of steel mini-implants. Only stainless steel implants had an altered, decreased hardness after exposure to CHX, although the same was found after their exposure to saliva. For patients undergoing orthodontic treatment with temporary anchorage units, CHX could be recommended for titanium, and probiotics for stainless steel mini-implants in oral-hygiene maintenance.

Comparative Evaluation of Biomechanical Performance of Titanium and Stainless Steel Mini Implants at Different Angulations in Maxilla: A Finite Element Analysis

Objective: To assess and compare the tensions and deformations (stresses and strains) generated after application of two types of forces (traction and torsion) in miniscrews of two different materials (titanium and stainless steel) placed at five different angulations. Materials and Methods: Three-dimensional models of the posterior maxillary area and the mini-implants were constructed using computer-aided design software program (CATIA P3 V5-6 R2015 B26 / 2016; Dassault Systèmes). Titanium and stainless steel materials were used for miniscrews. The area constructed was in between the maxillary second premolar and first molar. The models with mini-implants were inserted at five different angulations (30°, 45°, 60°, 75° and 90°). Torsional and tractional forces were applied on these implants, and the models were solved using ANSYS 10.0. Stress generated in implant and in the cortical and cancellous bones was evaluated and compared at all the five angulations. Results: Stress generated in stainless steel mini-implant during torsional and linear force application was less when compared with titanium mini-implant. Also, stress generated in implants of both materials increased as the angle increased from 30° to 90°. Difference in stress generated by stainless steel implant in the cortical bone for both linear and torsional forces was less when compared with titanium implant, whereas for cancellous bone, the difference was insignificant at all the angles. Conclusion: Irrespective of angles, difference in stress generated in stainless steel implants and titanium implants for both the forces was not significant, and hence, stainless steel implants can be used effectively in a clinical setting.

Micrographic study and torsional strength of grade 23 titanium mini-implants recycled for orthodontic purposes

The aim of this study was to identify the fracture resistance of grade 23 Titanium mini-implants recycled for orthodontic purposes and having stayed in the mouth during different periods of time. A total of 52 hybrid-designed titanium mini-implants, threaded length L=8mm, self-drilling and self-taping were used in 32 patients presenting orthodontic anomalies which required the use of mini-implants. Two types of tests were performed: polarizing optical imagery to assess the surface characteristics of the mini-implants (polarizing optical microscopy) and (mechanical) torsional strength tests, more quantitative, in order to establish the breaking point of the mini-implants during their re-use. For the mini-implants which had been in the mouth for a short period of time, (immediate removal or after two months of use), it must be noted that their surface characteristics revealed no defect at micron scale, the drilling head did not show any alteration, with a breaking point record of about 53Newton/cm2 (N/cm2). In contrast, the mini-implants, which had stayed in the mouth for 12 and 14 months, showed surface alterations especially at the "screw-gingiva" interface and the rupture stress ranges from 42 to 39N/cm2, respectively. Our results show that the resistance to fracture of the re-used mini-implants is inversely proportional to the duration of stay in the mouth.

Nanoparticles Deposition on Mini-implants for Osseo-integration and Antibacterial Properties Improvement

In last few years, researchers focused on improvement of lifespan of dental mini-implants by coating them with nanopoarticles for a better osseo-integration, which also possesses antibacterial properties. Once their surface is coated with nanoparticles type silver dopped hydroxyapatite makes them durable and safe by a good integration into tissue and by preventing bacterial infections. It is well known that a particular problem with medical devices such as dental mini-implants is bacterial colonization. For this reason the use of nanoparticles coated mini-implants is a measure to prevent or to treat infections caused by microbial agents present in oral cavity. Our study considers the possibility of using silver doped hydroxyapatite thin films on titanium mini-implants as an osseo-integration and antibacterial component. Therefore several physic-chemical analyses were performed in order to determine their properties and to open new perspectives to develop nanoparticulated thin films as coatings for orthodontic mini-implants.

Comparison of stress distribution on bone and mini-implants during en-masse retraction of maxillary anterior teeth in labial and lingual orthodontics: A three-dimensional finite element analysis

INTRODUCTION: In fixed orthodontic treatment, space closure is one of the most challenging aspects. The common method of en-masse retraction in sliding mechanics is the use of the elastomeric chain and power arm. Recently, titanium mini-implants are used as absolute sources of orthodontic anchorage. Lingual and labial bracket placement influences the pattern of tooth movement, but the stress that occurs around the teeth, the mini-implants, and the surrounding bone can be accurately mapped using a three-dimensional (3D) finite element method. AIM: The aim of this study was to evaluate the stress distribution on bone and mini-implants during en-masse retraction of maxillary anterior teeth in labial and lingual orthodontics with the help of finite element analysis. MATERIALS AND METHODS: Following the standard protocol for 3D finite element models, two models were created for en-masse retraction of the six anterior teeth: one model using the labial technique with the mini-implant placed at a height of 5 mm from the alveolar crest bucally and the second model using the lingual technique with the mini-implant placed at a height of 5 mm from the gingival margin palatally, and 200 g of retraction forces was given using a elastomeric chain. RESULTS AND CONCLUSIONS: The Von Mises stresses in the bone and mini-implant were significantly higher in the lingual technique as compared to the labial technique. The variations in stress patterns in the bone and the mini-implant in the labial and lingual technique could be the result of difference in the inter-bracket distance, point of force application, and its location to the center of resistance of the dentition.

A new synthetic granular calcium phosphate compound induces new bone in a sinus lift rabbit model

ObjectivesThe aim of this study was to investigate if a synthetic granular calcium phosphate compound (CPC) and a composite bisphosphonate-linked hyaluronic acid–calcium phosphate hydrogel (HABP·CaP) induced similar or more amount of bone as bovine mineral in a modified sinus lift rabbit model. Material and methodsEighteen adult male New Zeeland White rabbits, received randomly one of the two test materials on a random side of the face, and bovine mineral as control on the contralateral side. In a sinus lift, the sinus mucosa was elevated and a titanium mini-implant was placed in the alveolar bone. Augmentation material (CPC, HABP·CaP or bovine bone) was applied in the space around the implant. The rabbits were euthanized three months after surgery and qualitative and histomorphometric evaluation were conducted. Histomorphometric evaluation included three different regions of interest (ROIs) and the bone to implant contact on each installed implant. ResultsQualitative assessment (p = <.05), histomorphometric evaluations (p = < .01), and implant incorporation (p = <.05) showed that CPC and bovine mineral induced similar amount of bone and more than the HABP·CaP hydrogel. ConclusionCPC induced similar amount of bone as bovine mineral and both materials induced more bone than HABP·CaP hydrogel. Clinical significanceThe CPC is suggested as a synthetic alternative for augmentations in the maxillofacial area.

Topographical and elemental changes of retrieved stainless steel and titanium mini-implants after orthodontic treatment

ObjectiveTo investigate the surface changes and elemental composition of retrieved titanium and stainless steel orthodontic mini-implants and to determine the type of bone at the mini-implant–alveolar bone interface. Materials and methodsSurface characteristics, such as dullness, cracks, craters, and blunting of retrieved stainless steel and titanium mini-implants placed for orthodontic anchorage were studied with scanning electron microscopy and the change in composition was assessed with energy dispersive X-ray spectroscopy analysis. Bone tissue samples adjacent to mini-implant surface were examined histologically to identify the bone type. ResultsThe mean scores showed that the surface defects were 26% in titanium mini-implant threads and 33.33% of stainless steel mini-implant threads at the tip portion which were not statistically significant on comparison (P = 0.75). Comparing mean net wt% of carbon, oxygen, and nitrogen elements adsorbed on the surface of retrieved and control groups of titanium mini-implants yielded statistically significant results (P = 0.001). The histological sections of bone particles from mini-implant surface showed lamellar bone. ConclusionsBlunting (of the tips and threads) of all retrieved mini-implants were evident on SEM images and craters were observed in body region of retrieved stainless steel mini-implant. The retrieved titanium implants showed oxygen, carbon, calcium, and nitrogen on the surface, whereas only carbon and oxygen elements were found on retrieved stainless steel implants. The elemental oxygen (22.67%) was higher in the titanium group and a higher carbon (7.43%) in the stainless steel group. Numerous lacunae, resting lines, and osteocytes were found in bone tissue from mini-implant surface.

A Novel Rat Model of Polymicrobial Peri-Implantitis: A Preliminary Study.

Peri-implantitis is a complex polymicrobial biofilm-induced inflammatory osteolytic gingival infection that results in orofacial implant failures. To the best knowledge of the authors, there are no preclinical in vivo studies in implant dentistry that have investigated the inflammatory response to known microbial biofilms observed in humans. The aim of this study is to develop a novel peri-implant rat model using an established model of polymicrobial periodontitis. Wistar rats were used for the study of experimental peri-implantitis. One month after extraction of maxillary first molars, a titanium mini-implant was inserted. Two months after implant healing, implants were uncovered, and abutment fixing was done using cyanoacrylate to prevent abutment loosening. Rats were separated into two groups (group A: polymicrobial-infected and group B: sham-infected). One week after healing of abutments, rats were infected with Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia for 12 weeks. Bacterial colonization, bone resorption, and implant inflammation were evaluated by polymerase chain reaction (PCR), microcomputed tomography, and histology, respectively. Three rats with four implants in the infection group and two rats with three implants in the sham-infection group were analyzed. PCR analysis revealed presence of bacterial genomic DNA, and infection elicited significant immunoglobulin (Ig)G and IgM antibody responses, indicating bacterial colonization/infection around implants. Infection induced an enhanced mean distance from implant platform to the first bone-to-implant contact, extensive peri-implantitis with advanced bone resorption, and extensive inflammation with granulation tissue and polymorphonuclear leukocytes. To the best knowledge of the authors, this is the first study to develop a novel rat model of polymicrobial peri-implantitis. With modifications to improve implant retention it could offer significant advantages for studies of initiation and progression of peri-implantitis.

The integration of orthodontic miniscrews under mechanical loading: a pre-clinical study in rabbit.

Orthodontic miniscrews are an increasingly popular choice to achieve absolute anchorage. The temporary use of miniscrews and their recent introduction have limited the debate over the biological aspect of the materials to that of the surface that permeates the field of dental implants. The aim of the present study was to investigate the integration of grade 5 titanium mini-implants with machined or sand blasted acid etched surface (SAE) under mechanical load in a rabbit tibia model of implant integration. A total of 64 miniscrews (Ti6Al4V) of 1.5 mm diameter and 6.5 mm length were inserted in the proximal medial surface of each tibia in eight male rabbits aged 6 months. Each tibia received four miniscrews. A 100 g nickel-titanium coil spring (Neosentalloy) was applied between two miniscrews along the main axis while two miniscrews were left unloaded. The removal torque was measured for loaded and unloaded miniscrews after 12 weeks. Two miniscrews were harvested for histology. Removal torque was significantly higher for SAE mini-implants than for machined screws, under both loading conditions. Although no difference in bone to implant contact was observed among the groups, cortical area significantly decreased with both surfaces under loading. Our data indicate that SAE miniscrews have higher bone retention than MA miniscrews, although the effects of mechanical loading of these devices on cortical bone require further investigations.