Showing papers on "Osseointegration published in 2009"

Effects of implant surface coatings and composition on bone integration: a systematic review.

Abstract: Objective: The aim of the present review was to evaluate the bone integration efficacy of recently developed and marketed oral implants as well as experimental surface alterations. Materials and methods: A PubMed search was performed for animal studies, human reports and studies presenting bone-to-implant contact percentage or data regarding mechanical testing. Results: For recently developed and marketed oral implants, 29 publications and for experimental surface alterations 51 publications fulfilled the inclusion criteria for this review. Conclusions: As demonstrated in the available literature dealing with recently developed and marketed oral implants, surface-roughening procedures also affect the surface chemical composition of oral implants. There is sufficient proof that surface roughening induces a safe and predictable implant-to-bone response, but it is not clear whether this effect is due to the surface roughness or to the related change in the surface composition. The review of the experimental surface alterations revealed that thin calcium phosphate (CaP) coating technology can solve the problems associated with thick CaP coatings, while they still improve implant bone integration compared with non-coated titanium implants. Nevertheless, there is a lack of human studies in which the success rate of thin CaP-coated oral implants is compared with just roughened oral implants. No unequivocal evidence is available that suggests a positive effect on the implant bone integration of peptide sequences or growth factors coated on titanium oral implants. In contrast, the available literature suggests that bone morphogenetic protein-2 coatings might even impede the magnitude of implant-to-bone response.

Biology of implant osseointegration.

Abstract: Osseointegration refers to a direct structural and functional connection between ordered, living bone and the surface of a load-carrying implant. Currently, an implant is considered as osseointegrated when there is no progressive relative movement between the implant and the bone with which it has direct contact. A direct bone contact as observed histologically may be indicative of the lack of a local or systemic biological response to that surface. It is therefore proposed that osseointegration is not the result of an advantageous biological tissue response but rather the lack of a negative tissue response. The rationale of the present review is to evaluate the basic science work performed on the concept of biology of osseointegration, and to discuss the specific factors as they may relate to osseous healing around an implant.

Basic research methods and current trends of dental implant surfaces

Abstract: Among dental implant design alterations, surface modifications have been by far the most investigated topic. Regarding implant surface research, the lack of hierarchical approaches relating in vitro, in vivo, clinical trials, and ex vivo analyses has hindered biomaterials scientists with clear informed rationale guidelines for implant surface design. This manuscript provides a critical hierarchical overview of the in vitro, laboratory in vivo, clinical, and ex vivo methodologies used to investigate the performance of novel biomaterials aiming to allow dental professionals to better evaluate the past, present, and future dental implant surface research. This manuscript also contains an overview of the commercially available surface texture and chemistry modifications including novel nanotechnology-based fabrication processes. Over the last decade, surface texturing has been the most utilized parameter for increasing the host-to-implant response. Recently, dental implant surfaces utilizing reduced length scale physico/chemical features (atomic and nanometric) have shown the potential to synergistically use both texture and the inclusion of bioactive ceramic components on the surface. Although surface modifications have been shown to enhance osseointegration at early implantation times, information concerning its long-term benefit to peri-implant tissues is lacking due to the reduced number of controlled clinical trials. Given the various implants/surfaces under study, the clinician should ask, founded on the basic hierarchical approach described for the in vitro, laboratory in vivo data, as well as the results of clinical studies to effectiveness before use of any dental implant.

Titanium dioxide nanotubes enhance bone bonding in vivo.

Abstract: Implant topography is critical to the clinical success of bone-anchored implants, yet little is known how nano-modified implant topography affects osseointegration. We investigate the in vivo bone bonding of two titanium implant surfaces: titanium dioxide (TiO(2)) nanotubes and TiO(2) gritblasted surfaces. In previous in vitro studies, the topography of the TiO(2) nanotubes improved osteoblast proliferation and adhesion compared with gritblasted titanium surfaces. After four weeks of implantation in rabbit tibias, pull-out testing indicated that TiO(2) nanotubes significantly improved bone bonding strength by as much as nine-fold compared with TiO(2) gritblasted surfaces. Histological analysis confirmed greater bone-implant contact area, new bone formation, and calcium and phosphorus levels on the nanotube surfaces. It is anticipated that further studies will contribute to a better understanding of the effect of implant nanotopography on in vivo bone formation and bonding strength.

Are ceramic implants a viable alternative to titanium implants? A systematic literature review

Abstract: Aim: The aim of this systematic review was to screen the literature in order to locate animal and clinical data on bone–implant contact (BIC) and clinical survival/success that would help to answer the question ‘Are ceramic implants a viable alternative to titanium implants?’ Material and methods: A literature search was performed in the following databases: (1) the Cochrane Oral Health Group's Trials Register, (2) the Cochrane Central Register of Controlled Trials (CENTRAL), (3) MEDLINE (Ovid), and (4) PubMed. To evaluate biocompatibility, animal investigations were scrutinized regarding the amount of BIC and to assess implant longevity clinical data were evaluated. Results: The PubMed search yielded 349 titles and the Cochrane/MEDLINE search yielded 881 titles. Based upon abstract screening and discarding duplicates from both searches, 100 full-text articles were obtained and subjected to additional evaluation. A further publication was included based on the manual search. The selection process resulted in the final sample of 25 studies. No (randomized) controlled clinical trials regarding the outcome of zirconia and alumina ceramic implants could be found. The systematic review identified histological animal studies showing similar BIC between alumina, zirconia and titanium. Clinical investigations using different alumina oral implants up to 10 years showed survival/success rates in the range of 23 to 98% for different indications. The included zirconia implant studies presented a survival rate from 84% after 21 months to 98% after 1 year. Conclusions: No difference was found in the rate of osseointegration between the different implant materials in animal experiments. Only cohort investigations were located with questionable scientific value. Alumina implants did not perform satisfactorily and therefore, based on this review, are not a viable alternative to titanium implants. Currently, the scientific clinical data for ceramic implants in general and for zirconia implants in particular are not sufficient to recommend ceramic implants for routine clinical use. Zirconia, however, may have the potential to be a successful implant material, although this is as yet unsupported by clinical investigations.

Impact of Diabetes Mellitus and Glycemic Control on the Osseointegration of Dental Implants: A Systematic Literature Review

Abstract: Background: Implant treatment is an attractive substitute to traditional fixed/removable prosthetic appliances. In patients with diabetes, dental implant therapy has been considered a contraindication. Hyperglycemia augments the severity of periodontal disease, and glycemic control is an essential variable in determining the success of dental implants in subjects with diabetes. Subjects with well-controlled diabetes may not be significantly compromised and can have high dental implant success rates compared to individuals with poorly controlled diabetes. The focused questions addressed in this systematic review were as follows: Can patients with diabetes be good candidates for dental implant therapy? And how does hyperglycemia and glycemic control influence osseointegration? Methods: A systematic literature search of MEDLINE/PubMed articles published from 1982 up to and including July 2009 was independently performed by two investigators. In addition, reference lists of original and review articles were searched. The search strategy was to use the following terms in different combinations: dental implants, immediate implants, osseointegration, periodontal disease, diabetes, hyperglycemia, metabolic control, and glycemic control. The search included studies on humans and diabetes-induced animal models. The selection criteria included all levels of available evidence. Suitable variables included the implant survival rate among individuals with diabetes, effects of hyperglycemia and glycemic control on bone, and maintenance of dental implants in subjects with diabetes. Articles published only in the English language were considered, and unpublished data were not sought. Results: We initially identified 33 studies. Fifteen studies, which did not fulfill the selection criteria, were excluded. The included studies reported that poorly controlled diabetes negatively affects implant osseointegration; however, under optimal serum glycemic control, osseointegration can successfully occur in patients with diabetes. Animal studies have confirmed that osseointegration can be successfully achieved in insulincontrolled rats with diabetes, whereas in uncontrolled rats with diabetes, the bone-to-implant contact appears to decrease with time. The use of antiseptic mouthrinses and oral-hygiene maintenance helps in achieving a successful dental implant osseointegration in subjects with diabetes. Conclusion: A successful dental implant osseointegration can be accomplished in subjects with diabetes with good metabolic control (serum glycemic level and hemoglobin A1c in normal range) in a similar manner as in subjects without diabetes. J Periodontol 2009;80:1719-1730.

Randomized-controlled clinical trial of customized zirconia and titanium implant abutments for single-tooth implants in canine and posterior regions: 3-year results.

Abstract: Objectives: The aim was to test whether or not zirconia abutments exhibit the same survival and technical / biological outcome as titanium abutments. Material and methods: Twenty-two patients receiving 40 single-tooth implants in canine and posterior regions were included. The implant sites were randomly assigned to 20 zirconia and 20 titanium abutments. All-ceramic and metal-ceramic crowns were fabricated. At baseline, 6, 12 and 36 months, the reconstructions were examined for technical and biological problems. Probing pocket depth (PPD), plaque control record (PCR) and bleeding on probing (BOP) were assessed at abutments (test) and analogous contralateral teeth (control). Standardized radiographs of the implants were made and the bone level (BL) was measured referring to the implant shoulder on mesial (mBL) and distal sides (dBL). The difference of color (DeltaE) of the peri-implant mucosa and the gingiva of control teeth was assessed with a spectrophotometer. The data were statistically analyzed with Mann-Whitney Rank and Student's unpaired t-tests. Results: Eighteen patients with 18 zirconia and 10 titanium abutments were examined at a mean follow-up of 36 months (range 31.5-53.3 months). No fracture of an abutment or loss of a reconstruction was found. Hence, both exhibited 100% survival. At two metal-ceramic crowns supported by titanium abutments chipping of the veneering ceramic occurred. No difference of the biological outcome of zirconia and titanium abutments was observed: PPD ( 3.2 +/- 1 mm, mPPD(Ti) 3.4 +/- 0.5 mm), PCR ( 0.1 +/- 0.2, mPCR(Ti) 0.1 +/- 0.2) and BOP ( 0.4 +/- 0.4, mBOP(Ti) 0.2 +/- 0.3). Furthermore, the BL was similar at implants supporting zirconia and titanium abutments ( 1.7 +/- 1, 1.6 +/- 1; mBL(Ti) 2 +/- 1, dBL(Ti) 2.1 +/- 1). Both, zirconia and titanium abutments induced a similar amount of discoloration of the mucosa compared with the gingiva at natural teeth ( 9.3 +/- 3.8, DeltaE(Ti) 6.8 +/- 3.8). Conclusions: At 3 years, zirconia and titanium abutments exhibited same survival and technical, biological and esthetical outcomes. To cite this article: Zembic A, Sailer I, Jung RE, Hammerle CHF. Randomized-controlled clinical trial of customized zirconia and titanium implant abutments for single-tooth implants in canine and posterior regions: 3-year results. Clin. Oral Impl. Res. xx, 2009; 000-000.

Implant micromotion is related to peak insertion torque and bone density

Abstract: Objectives: Measuring peak insertion torque in relation to different bone densities, the present study seeks to determine whether micromotion at the interface is related to primary stability achieved by increasing insertion torque. Material and methods: A total of 120 Ti-Bone implants were placed in fresh bovine bone samples representing three density categories: hard, normal and soft (HNS). Five groups of peak insertion torque (20, 35, 45, 70 and 100N/cm) were evaluated in the three bone density categories noted. Customized electronic equipment connected to a PC was used to register the peak and other insertion torque data. A loading device, consisting of a digital force gauge and a digital micrometer, was used to measure the micromovements of the implant during the application of 20, 25 and 30N lateral forces. The data were analyzed for statistical significance by ANOVA and Spearman’s rank correlation coefficient tests. Results: A statistically significant difference between implant micromobility placed with different levels of torque and in different bone densities was demonstrated by ANOVA. Spearman’s rank correlation coefficient showed a high dependency between the peak insertion torque and the observed micromovement. Particularly, in soft bone, it was not possible to achieve more than 35N/cm of peak insertion torque. Conclusions: Results showed that increasing the peak insertion torque reduces the level of implant micromotion. In addition, micromotion in soft bone was found to be consistently high, which could lead to the failure of osseointegration. Thus, immediate functional loading of implants in soft bone should be considered with caution.

Potential of chemically modified hydrophilic surface characteristics to support tissue integration of titanium dental implants.

Abstract: In the past, several modifications of specific surface properties such as topography, structure, chemistry, surface charge, and wettability have been investigated to predictably improve the osseointegration of titanium implants. The aim of the present review was to evaluate, based on the currently available evidence, the impact of hydrophilic surface modifications of titanium for dental implants. A surface treatment was performed to produce hydroxylated/hydrated titanium surfaces with identical microstructure to either acid-etched, or sand-blasted, large grit and acid-etched substrates, but with hydrophilic character. Preliminary in vitro studies have indicated that the specific properties noted for hydrophilic titanium surfaces have a significant influence on cell differentiation and growth factor production. Animal experiments have pointed out that hydrophilic surfaces improve early stages of soft tissue and hard tissue integration of either nonsubmerged or submerged titanium implants. This data was also corroborated by the results from preliminary clinical studies. In conclusion, the present review has pointed to a potential of hydrophilic surface modifications to support tissue integration of titanium dental implants.

Strategies to affect bone remodeling: Osteointegration

Abstract: Osteointegration was defined as a "direct structural and functional connection between ordered living bone and the surface of a load-carrying implant." Although osteointegration was meant originally to describe a biologic fixation of the titanium dental implants, it is now used to describe the attachment of other materials used for dental and orthopedic applications as well. Analyses of material-bone interface showed that osteointegrated implants can have an intervening fibrous layer or direct bone apposition characterized by bone-bonding depending on the composition and surface properties of the biomaterial. This article reviews biologic (host tissue properties and response), biomechanical, and biomaterial factors affecting osteointegration. Biologic factors include the quality of bone. Biomaterial factors include the effect of material composition on the bone-material interface. Suggested areas for future research include determining the correlation between oral bone status and osteoporosis, the effect of gender, age, and endocrine status (e.g., osteoporosis) on implant success or failure, the effect of calcium phosphate coating composition and crystallinity on in vivo performance of implants, the factors contributing to accelerated osteointegration, and development of osteoinductive implants.

Re-osseointegration on previously contaminated surfaces : a systematic review

Abstract: Objectives: The aim of this review was to search the literature for the existing evidence of re-osseointegration after treatment of peri-implantitis at contaminated implant surfaces. Material and Methods: A search of PubMed as well as additional hand search of articles were conducted. Publications and articles accepted for publication up to November 2008 were included. Results: A total of 25 animal studies fulfilled the inclusion criteria for this review. Access surgery with closed healing has been observed to positively influence the rate of re-osseointegration when compared with non-surgical decontamination of the implant surface with open healing. Open debridement including surface decontamination may result in re-osseointegration and this integration was more pronounced on rougher than on smooth implant surfaces. The adjunctive use of regenerative procedures resulted in varying amounts of re-osseointegration. Conclusions: Re-osseointegration is possible to obtain on a previously contaminated implant surface and can occur in experimentally induced peri-implantitis defects following therapy. The amount of re-osseointegration, varied considerably within and between studies. Implant surface characteristics may influence the degree of re-osseointegration. Surface decontamination alone can not achieve substantial re-osseointegration on a previously contaminated implant surface. No method predictably accomplished complete resolution of the peri-implant defect.

Bioactive SrTiO(3) nanotube arrays: strontium delivery platform on Ti-based osteoporotic bone implants.

Abstract: Development of strontium releasing implants capable of stimulating bone formation and inhibiting bone resorption is a desirable solution for curing osteoporosis. In this work, well-ordered SrTiO3 nanotube arrays capable of Sr release at a slow rate and for a long time are successfully fabricated on titanium bysimplehydrothermaltreatmentofanodizedtitaniananotubes.Thissurfacearchitecturecombinesthefunctions of nanoscaled topography and Sr release to enhance osseointegration while at the same time leaving space for loading of other functional substances.In vitroexperiments reveal that the SrTiO3nanotube arrays possess good biocompatibility and can induce precipitation of hydroxyapatite from simulated body fluids (SBF). This Ti-based implant with SrTiO3nanotube arrays is an ideal candidate for osteoporotic bone implants. The proposed method can also be extended to load other biologically useful elements such as Mg and Zn.

Osseointegration of zirconia and titanium dental implants: a histological and histomorphometrical study in the maxilla of pigs

Abstract: Objectives: The purpose of the present study was to histologically compare the bone tissue responses to surface-modified zirconia and titanium implants. Methods: Threaded zirconia implants were produced using a new low-pressure injection moulding technique and thereafter surface treated by acid etching. Titanium implants with the exact shape and surface treated by sandblasting and acid etching (SLA) served as controls. Fifteen adult pigs received both implant types in the maxilla 6 months after extraction of the second and third incisors. The animals were sacrificed after 4, 8 and 12 weeks and 30 implants with surrounding bone were retrieved. Results: Histological evaluation showed osseous integration for both materials. Zirconia implants revealed mean peri-implant bone density values of 42.3% (SD � 14.5) at 4 weeks,

The roles of surface chemistry and topography in the strength and rate of osseointegration of titanium implants in bone.

Abstract: The present study investigated the effects of surface chemistry and topography on the strength and rate of osseointegration of titanium implants in bone. Three groups of implants were compared: (1) machine-turned implants (turned implants), (2) machine-turned and aluminum oxide-blasted implants (blasted implants), and (3) implants that were machine-turned, aluminum oxide-blasted, and processed with the micro-arc oxidation method (Mg implants). Three and six weeks after implant insertion in rabbit tibiae, the implant osseointegration strength and rate were evaluated. Surface chemistry revealed characteristic differences of nine at.% Mg for Mg implants and 11 at.% Al for blasted implants. In terms of surface roughness, there was no difference between Mg implants and blasted implants in developed surface ratio (Sdr; p = 0.69) or summit density (Sds; p = 0.96), but Mg implants had a significantly lower arithmetic average height deviation (Sa) value than blasted implants (p = 0.007). At both 3 and 6 weeks, Mg implants demonstrated significantly higher osseointegration strength compared with turned (p = 0.0001, p = 0.0001) and blasted (p = 0.0001, p = 0.035) implants, whereas blasted implants showed significantly higher osseointegration than turned implants at 6 weeks (p = 0.02) but not at 3 weeks (p = 0.199). The present results not only support the hypothesis that biochemical bonding facilitates rapid and strong integration of implants in bone, but also provide evidence for biochemical bonding theory previously proposed by Sul.

Nanotechnology for bone materials.

Abstract: It has been established that for orthopedic-related research, nanomaterials (materials defined as those with constituent dimensions less than 100 nm in at least one direction) have superior properties compared to conventional counterparts This review summarizes studies that have demonstrated enhanced in vitro and in vivo osteoblast (bone-forming cells) functions (such as adhesion, proliferation, synthesis of bone-related proteins, and deposition of calcium-containing mineral) on nanostructured metals, ceramics, polymers, and composites thereof compared to currently used implants These results strongly imply that nanomaterials may improve osseointegration, which is crucial for long-term implant efficacy This review also focuses on novel drug-carrying magnetic nanoparticles designed to treat various bone diseases (such as osteoporosis) Although further investigation of the in vivo responses and toxicity of these novel nanomaterials pertinent for orthopedic applications are needed, nanotechnology clearly has already demonstrated the ability to produce better bone implants and therefore should be further investigated Copyright © 2009 John Wiley & Sons, Inc For further resources related to this article, please visit the WIREs website

Bodily distalization of molars with absolute anchorage.

Abstract: Palatal implants have been used over the last two decades to eliminate headgear wear and to establish stationary anchorage. In this case report, the stability of a palatal implant for distalization of molars bodily and for anchorage maintenance was assessed. The implant was a stepped screw titanium (4.5 mm diameter 3 8 mm length), and it was placed in the palatal region for orthodontic purposes. A surgical template containing a metal drill housing was prepared. Angulation of the drill housing was controlled according to the radiologic tracing of the maxilla transferred to a plaster cast section in the paramedian plane. The implant was placed using a noninvasive technique (incision, flap, and suture elim- ination) and left transmucosally to facilitate the surgical procedure and to reduce the number of operations. The paramedian region was selected (1) to avoid the connective tissues of the palatine suture and (2) because it is considered to be a suitable host site for implant placement. After three months of healing, the implant was osseointegrated and orthodontic treatment was initiated. For molar distalization, the Keles Slider appliance was modified and, instead of a Nance button, a palatal implant was used for anchorage. The results showed that the molars were distalized bodily at five months, and no anchorage loss was observed. At the end of the treatment, the smile was improved, and an ideal Class I molar and canine relationship, an ideal overbite, and an ideal overjet were all achieved. In conclusion, palatal implants can be used effectively for anchorage maintenance and in space-gaining procedures. Use of a three-dimensional surgical template eliminated implant placement errors, reduced chair time, minimized trauma to the tissues, and enhanced osseointegration. This method can be used effectively to achieve distalization of molars bodily without anchorage loss. (Angle Orthod 2003;73:471-482.)

Implant placement in patients with oral bisphosphonate therapy: a case series.

Abstract: Background: Although the effect of bisphosphonates on dental implant osseointegration is not clear, dental implant failures attributable to oral bisphosphonate therapy have been reported in patients with osteoporosis. Purpose: The aim of this study was to evaluate implant survival in patients with a history of bisphosphonate therapy in a retrospective survey. Materials and Methods: A total of 46 ITI implants placed in 21 osteoporotic patients (females; average age 53 years, range 42–79 years) were evaluated with regard to probing depth, mobility, thread exposure, and bleeding on probing. All patients were under oral bisphosphonate therapy. Results: None of implants showed mobility and all patients could be considered free from peri-implantitis. Time of bisphosphonate therapy before and after implant insertion showed no statistically significant influence on PD, BOP, and TE. Likewise, implant location, prosthetic type, and opposing dentition had no statistically significant influence on the clinical and radiological parameters of implants. Conclusion: Within the limitations of this study, it could be concluded that neither being on oral bisphosphonate treatment before implant placement nor starting bisphosphonate therapy after implant installation might jeopardize the successful osseointegration and clinical and radiographic condition of the implants.

Effects of Simvastatin on bone healing around titanium implants in osteoporotic rats.

Abstract: Objectives: Osteoporosis is known to impair the process of implant osseointegration. The recent discovery that statins (HMG-CoA reductase inhibitors) act as bone anabolic agents suggests that statins can be used as potential agents in the treatment of osteoporosis. Therefore, we hypothesized that statins will promote osteogenesis around titanium implants in subjects with osteoporosis. Material and methods: Fifty-four female Sprague Dawley rats, aged 3 months old, were randomly divided into three groups: Sham-operated group (SHAM; n=18), ovariectomized group (OVX; n=18), and ovariectomized with Simvastatin treatment group (OVX+SIM; n=18). Fifty-six days after being ovariectomized (OVX), screw-shaped titanium implants were inserted into the tibiae. Simvastatin was administered orally at 5 mg/kg each day after the placement of the implant in the OVX+SIM group. The animals were sacrificed at either 28 or 84 days after implantation and the undecalcified tissue sections were obtained. Bone-to-implant contact (BIC) and bone area (BA) within the limits of implant threads were measured around the cortical (zone A) and cancellous (zone B) bone regions. Furthermore, bone density (BD) of zone B in a 500 μm wide zone lateral to the implants was also measured. Results: There were no significant differences in BIC and BA measurements in zone A in any of the three groups at either 28 or 84 days after implantation (P>0.05). By contrast, in zone B, significant differences in the measurement of BIC, BA, and BD were observed at 28 and 84 days between all three groups. Bone healing decreased with lower BIC, BA, and BD around implant in OVX group compared with other two groups, and Simvastatin reversed the negative effect of OVX on bone healing around implants with the improvement of BIC, BA, and BD in zone B. Conclusion: Osteoporosis can significantly influence bone healing in the cancellous bone around titanium implants and Simvastatin was shown to significantly improve the osseointegration of pure titanium implants in osteoporotic rats.

Double-blind randomized controlled trial study on post-extraction immediately restored implants using the switching platform concept: soft tissue response. Preliminary report.

Abstract: AIM To evaluate the soft tissue response to immediately placed implants using the platform switching concept. MATERIAL AND METHODS In 22 patients, 22 implants of 5.5 mm platform diameter were placed immediately into fresh extraction sockets in maxillae without compromised bone tissue. Eventual post-extraction bone defects were filled using bovine bone matrix mixed with collagen. Immediately after insertion, implants were randomly divided: 11 implants were connected with a 3.8 mm diameter abutment (test group) and 11 with a 5.5 mm diameter abutment (control group). A provisional crown was adapted and adjusted for non-functional immediate positioning. Two months later, definitive prosthetic rehabilitation was performed. Periodontal parameter, buccal peri-implant mucosal changes (REC), mesial and distal papilla height (PH) and vertical height of jumping distance (VHG) were measured at the time of implant placement, of definitive prosthesis insertion and every 6 months thereafter. RESULTS The mean follow-up was 25 months. All implants were clinically osseointegrated. The test group showed a +0.18 mm REC gain. PH gain was +0.045 mm on average. The mean values were statistically significant (P< or =0.005) compared with the control group (PH=-0.88 mm; REC=-0.45 mm). No difference between the two groups in periodontal parameters was found. The mean value of bone filling was 7.51 mm in the test group (97.4% of VHG) and 8.57 mm in the control group (95.2% of VHG). No statistically significant difference was found between the two groups. CONCLUSIONS This study suggests that, in a limited time period of 2 years, immediately placed implants with subsequent platform switching can provide peri-implant tissue stability.

A prospective multicenter 5-year radiographic evaluation of crestal bone levels over time in 596 dental implants placed in 192 patients

Abstract: Background: Dental implants have been used to replace missing teeth to provide function and esthetics. One goal of such restorations is to maintain host tissue around the implants. The purpose of this prospective multicenter human clinical trial was to evaluate radiographic marginal bone levels around non-submerged hollow cylindrical and solid-screw implants for 5 years after loading.Methods: Patients older than 18 years of age with sufficient native bone to surround a dental implant without imposing on a vital structure were recruited at five sites. Solid-screw or hollow-cylinder implants with a titanium plasma–sprayed implant surface were placed in the anterior maxilla or anterior mandible and restored with fixed restorations. Baseline radiographs were taken at the time of implant placement. Subsequent radiographs were taken at the time of final prosthesis placement, at 6 months after prosthesis placement, and annually from prosthesis placement for 5 years.Results: The results of 596 implants in 192 pat...

Influence of Implant Connection Type on the Biomechanical Environment of Immediately Placed Implants – CT-Based Nonlinear, Three-Dimensional Finite Element Analysis

Abstract: Purpose: The purpose of the present study was to evaluate the biomechanical environment of immediately placed implants, before and after osseointegration, by comparing three different implant-abutment connection types. Materials and Methods: A computer tomography-based finite element model of an upper central incisor extraction socket was constructed containing implants with either external hex, internal hex, or Morse-taper connection. Frictional contact elements were used in the bone, implant, abutment, and abutment screw interfaces in the immediately placed simulations. In osseointegrated simulations, the repair of bone alveolar defect and a glued bone-to-implant interface were assumed. By analysis of variance, the influence was assessed of connection type, clinical situation, and loading magnitude on the peak equivalent strain in the bone, peak von Mises stress in the abutment screw, bone-to-implant relative displacement, and abutment gap. Results: The loading magnitudes had a significant contribution, regardless of the assessed variable. However, the critical clinical situation of an immediately placed implant itself was the main factor affecting the peak equivalent strain in the bone and bone-to-implant displacement. The largest influence of the connection type in this protocol was seen on the peak equivalent stress in the abutment screw. On the other hand, a higher influence of the various connection types on bone stress/strain could be noted in osseointegrated simulations. Conclusions: The implant-abutment connection design did not significantly influence the biomechanical environment of immediately placed implants. Avoiding implant overloading and ensuring a sufficient initial intraosseous stability are the most relevant parameters for the promotion of a safe biomechanical environment in this protocol.

Design optimization of functionally graded dental implant for bone remodeling

Abstract: Despite a great success, one of the key issues facing in dental implantation clinic is a mismatch of mechanical properties between engineered and native biomaterials, which makes osseointegration and bone remodeling problematical. Functionally Graded Material (FGM) has been proposed as a potential upgrade to some conventional implant materials like titanium for selection in prosthetic dentistry. The idea of FGM dental implant is that the property would vary in a certain pattern to match the biomechanical characteristics required at different regions in the hosting bone. However, mating properties do not necessarily guarantee the best osseointegration and bone remodeling. No existing report has been available to develop an optimal design of FGM dental implant for promoting a long-term success. This paper aims to explore this critical issue by using the computational bone remodeling and design optimization. A buccal–lingual sectional model, which consists of a single unit implant and four other adjacent teeth, was constructed from computerized tomography (CT) scan images. Bone remodeling induced by use of various FGM dental implants is calculated over the period of 4 years. Based upon remodeling results, response surface method (RSM) is adopted to develop a multi-objective optimal design for FGM implantation FGM designs.

Five-year results of fixed implant- supported rehabilitations with distal cantilevers for the edentulous mandible

Abstract: Objectives: The purpose of this study was to evaluate the survival rate, success rate and primary complications associated with mandibular fixed implant-supported rehabilitations with distal cantilevers over 5 years of function. Material and methods: In this prospective multi-center trial, 45 fully edentulous patients were treated with implant-supported mandibular hybrid prostheses with distal extension cantilevers. Data were collected at numerous time points, including but not limited to: implant placement, abutment placement, final prosthesis delivery, 3 months and 5 years post-loading. Biological, implant and prosthetic parameters defining survival and success were evaluated for each implant including: sulcus bleeding ndex (SBI) at four sites per implant, width of facial and lingual keratinized gingiva (mm), peri-implant mucosal level (mid-facial from the top of the implant collar, measured in mm), modified plaque index (MPI) at four sites per implant, mobility and peri-implant radiolucency. Survival was defined as implants or prostheses that did not need to be replaced. Success rate was defined as meeting well-established criteria that were chosen to indicate healthy peri-implant mucosa osseointegration, prostheses success and complications. Results: A total of 237 implants in 45 completely edentulous patients were included in the study. In each patient, four to six implants were placed to support hybrid prostheses with distal cantilevers. Cantilevers ranged in length from 6 to 21 mm, with an average length of 15.6 mm. The ages of the patients ranged from 34 to 78 with a mean age of 59.5 years. The survival rate of implants was 100% (237/237) and for prostheses 95.5% (43/45). The overall treatment success rate was calculated as 86.7% (39/45). Of the six patients that have not met the criteria for success, two patients required replacement of the entire prosthesis and four patients presented 4four complications events. Conclusion: Fixed implant-supported rehabilitation with distal cantilever resulted in a reliable treatment modality over the 5-year observation period. Although biological parameters of MPI, SBI, keratinized tissue and peri-implant mucosal levels showed statistically significant differences over time, the mean values for each patient remained within the normal limits of oral health. Complications were categorized as biological or technical. The majority of complications were technical complications (54/79) and of these most involved fracture of the acrylic teeth and base (20/54). While the survival rate was 100% for implants and 95.5% for prostheses, the application of strict criteria for treatment success resulted in an overall treatment success rate of 86.7%. Date: