Gruber R, Nadir J, Haas R.
Department of Oral Surgery, Medical University of Vienna, Währingerstrasse 25a,
1090 Vienna, Austria.
interleukin-1beta (IL-1) in the crevicular fluid of dental implants that were
placed and restored immediately after extraction of teeth. The crevicular fluid
of 11 patients was obtained before the teeth were extracted and during the early
(days 1-10) and late (day 10 onwards) follow-up periods. Samples were analysed by
kinetic assay for neutrophil elastase and by immunoassay of IL-1. The absolute
values remained unchanged during the early (p=0.15; p=0.2) and late (p=0.4;
p=0.5) follow-up periods. Paired analysis showed that the absolute values in the
periodontal crevicular fluid were similar compared with the corresponding samples
obtained during the early (p=0.5; p=0.3) and the late (p=0.6; p=0.2) follow-up
periods. These findings suggest that placement of implants according to the
immediate loading protocol, although it is an invasive procedure, does not
provoke an inflammatory reaction.
Begg T, Geerts GA, Gryzagoridis J.
Department of Restorative Dentistry, University of the Western Cape, Tygerberg,
distal implants at an angle. The purpose of this study was to do a qualitative
descriptive analysis of stress patterns around the distal angled implant of the
All-on-Four concept. MATERIALS AND METHODS: Four photoelastic acrylic resin
models, each with four implants simulating the All-on-Four configuration, were
prepared. The two central implants were placed vertically and parallel in each
model, and the distal implant on each side was placed at an increasing angle (0,
15, 30, and 45 degrees) in each model. The four implants were splinted by means
of a cast metal bar. The photoelastic models were placed between two parallel
anvils. Pairs of abutments were systematically subjected to a load by suspending
5-, 10-, and 15-kg weights from one of the anvils. Photoelastic analysis was
accomplished using a circular polariscope. The fringe patterns produced in the
photoelastic resin for each implant and load were photographed with a digital
camera. Fringe concentrations and the highest fringe order were recorded and
described for the apical, central, and coronal regions of the distal angled
implant for each load scenario. RESULTS: For the implants placed at 15- and
and for all angulations, the lowest fringe order was recorded at the central
region of the implant. The highest fringe order for the apical region was always
higher than the highest fringe order for the coronal region of the implant.
Experimental immediate loading of dental implants in conjunction with grafting procedures.
Neugebauer J, Iezzi G, Perrotti V, Fischer JH, Khoury F, Piattelli A, Zoeller JE.
Interdisciplinary Department for Oral Surgery and Implantology, University of
Cologne, Cologne, Germany.
in six mini pigs. Before implant placement, crestal or apical defects were
created, which were treated with bone chips, phycogene hydroxyapatite (HA),
bovine HA, or bovine HA enhanced with a synthetic peptide. Crestal grafts were
stabilized with titanium membranes. All bridges were in function and showed signs
of chewing wear after 4-month loading. Three out of 107 implants showed no
osseointegration (2.7%). Most of the crestal defects showed incomplete
regeneration, due to an infection of the membranes (74.3%) The difference in
height between surgical and remaining defect was calculated as defect
development, which was 2.3 +/- 2.08 mm for bone chips with an area of regenerated
bone of 22.8 +/- 3.34% and 0.7 +/- 2.22 mm for phycogene HA with 11.3 +/- 4.36%
regenerated bone. Bovine HA showed an increase of defects 1.3 +/- 2.47 mm with
only 7.9 +/- 1.7% bone regeneration. Bovine HA enhanced with a peptide showed a
defect development of 1.1 +/- 1.42 mm with an area of regenerated bone of 18.2
+/- 2.38%. In conclusion, local grafting procedures did not disturb the course of
osseointegration for immediate loaded implants if primary stability was reached.
The regeneration of apical defects was uneventful even with immediate loading.
Crestal defects required membrane fixation with a careful flap elevation to avoid
membrane exposure and loss of the graft.
Flanagan D, Ilies H, Lasko B, Stack J.
for many partially edentulous and edentulous patents. Immediate loading of newly
Kökat AM, Cömert A, Tekdemir I, Akkocaoğlu M, Akça K, Cehreli MC.
Department of Prosthodontics, Yeditepe University, Goztepe, Istanbul.
around immediately-loaded implants supporting mandibular fixed prostheses with
regard to number of implant support. MATERIALS: Linear strain gauges were bonded
on the labial bone of 5 Straumann dental implants placed in the mandibular
symphysis region of 2 completely edentulous mandibles of fresh human cadavers.
Installation torque value of each implant was measured by a custom-made torque
wrench and resonance frequency analyses were undertaken. A one-piece full-arch
fixed prosthesis was fabricated for each cadaver and 2 miniature load cells were
integrated in the cantilever region of the prostheses for controlled loading
experiments. 5-, 4-, and 3-implant support designs were consecutively tested.
Strain measurements were performed at a sample rate of 10 KHz and under a maximum
load of 100 N, simultaneously monitored from a computer connected to data
acquisition system. RESULTS: The installation torque values and implant stability
quotient values of the implants ranged between 42.12 to 145.67 N cm and 61 to 80,
respectively. Between-group comparisons revealed that the highest strain
magnitudes were recorded for the 3-implant design followed by the 4- and
5-implant designs, although there was a tendency toward similar load partitioning
between 4- and 5-implant designs (P < 0.05). CONCLUSIONS: Bone strains around
In vitro evaluation of the influence of the cortical bone on the primary stability of two implant systems.
Andrés-García R, Vives NG, Climent FH, Palacín AF, Santos VR, Climent MH, Bullón
Faculty of Dentistry, University of Seville, Spain. firstname.lastname@example.org
of the main requirements for its implementation is obtaining appropriate primary
stability in implants. With that aim, conical implants are commercially
available, since, according to specialized literature, they provide greater
stability. One of the methods to measure implant stability which has evolved to
further stages is resonance frequency analysis (RFA). In the present paper we
attempt to evaluate the influence of the cortical bone on the primary stability
of two implants of similar diameter and length. STUDY DESIGN: 15 fresh cow ribs
were selected and six different implant beds were prepared in each. These
preparations corresponded to two different implant systems: A Swiss Plus from
Zimmer Dental and an Mk IV from Nobel Biocare. Two drilling protocols were used
for soft bone, hard bone and bone without cortical. After preparing the beds, the
implants were placed and implant primary stability was measured with the Osstell
mentor. RESULTS: Higher ISQ (Implant Stability Quotient) values were observed for
both implant systems when the cortical bone is maintained than when it is
eliminated, the difference being statistically significant in the case of Mk IV
implants. CONCLUSIONS: The results from this study show the importance of
preserving cortical bone during drilling in order to obtain greater primary
The Effects of Superficial Roughness and Design on the Primary Stability of Dental Implants.
Dos Santos MV, Elias CN, Cavalcanti Lima JH.
Biomaterials Laboratory, Instituto Militar de Engenharia, Rio de Janeiro, RJ,
this work was to analyze the influence of the design and surface morphology on
the primary stability of dental implants. The insertion torque and resonance
frequency analysis (RFA) were the parameters used to measure the primary
stability of the implants. Materials and Methods: Thirty implants, divided in six
groups of five samples were placed in cylinder of high molecular weight
polyethylene. The groups were different upon two designs (cylindrical and conic)
and three implant surfaces finishing (machined, acid etched, and anodized). The
insertion torque was quantified by a digital torque driver (Lutron Electronic
Enterprise Co., Taipei, Taiwan) and the resonance frequency was measured by
Osstell mentor (Integration Diagnostics AB, Göteborg, Sweden). The implant
surface morphology was characterized by scanning electron microscopy, roughness
measurement, and friction coefficient. Results: The machined implants showed
smaller insertion torques than treated implant surfaces. There were no
differences between the RFA measurements in all tested surfaces. Statistical
analyses demonstrated no correlation between the dental implant insertion torque
and primary stability measured by the RFA. The implants with treated surfaces
showed greater roughness, a higher friction coefficient, and demanded a larger
insertion torque than machined implants. The results of the surface roughness and
friction coefficients are in accordance with the results of the insertion torque.
The difference, across the insertion torque values, between conical and
cylindrical implants, can be explained by the different contact surface area
among the thread geometry of these implants. Conclusion: The maximum implant
insertion torque depends on the implant geometry, thread form, and implant
surface morphology. The placement of conical implants with treated surfaces
required the highest insertion torque. There was no correlation between RFA and
insertion torque implant.
Implant micromotion is related to peak insertion torque and bone density.
Trisi P, Perfetti G, Baldoni E, Berardi D, Colagiovanni M, Scogna G.
Laboratory of Biomaterials and Biomechanics, Galeazzi Orthopaedic Institute,
University of Milano, Milano, Italy. email@example.com
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 100 N/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 30 N 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 35 N/cm of peak insertion torque. CONCLUSIONS: Results showed that
Histomorphometric evaluation of implant design as a key factor in peri-implant bone response: a preliminary study in a dog model.
[Article in English, Italian]
Orsini E, Salgarello S, Bubalo M, Lazic Z, Trire A, Martini D, Franchi M, Ruggeri
Department of Human Anatomy, University of Bologna, Bologna, Italy.
contact (BIC) plays a major role in long-term successful implant
osseointegration. Numerous factors influencing this initial stability have been
studied. This preliminary in vivo study on a dog lower jaw aimed to investigate
the hypothesis that primary implant stability in low density bone may be
influenced by implant design. METHODS: The authors compared two different implant
designs with regard to their immediate quantitative relation to host bone (BIC%
and gap area, GA%). The screw-shaped implants, manufactured by Or-Vit
placed in dog jaw after complete osseous healing of the extractive sockets,
according to a delayed implantation procedure. Five hours after surgery the
animal was sacrificed. Radiographic, histological, morphometric and
ultrastructural analysis were performed. RESULTS: An inverse relation existed
among the two parameters BIC and GA: GA, as a region with high osteogenetic
potentiality, appeared wider in WP implants; BIC, as the expression of primary
mechanical stability, was higher in NP implants. CONCLUSION: Based on this
Slaets E, Naert I, Carmeliet G, Duyck J.
Department of Prosthetic Dentistry, BIOMAT Research Group, K.U., Leuven, Belgium.
of the bone healing responses. MATERIAL AND METHODS: Implants were placed in
rabbit tibial diaphyses and left to heal for 3, 7, 14, 28 or 42 days. Half of the
animals received an immediate loading protocol of 2.2 N at 3 Hz for 1800 cycles
and 5 days/week, whereas the others served as unloaded controls. Histological
assessment was combined with histomorphometrical measurements. RESULTS: At early
time-points, an endosteal and periosteal new bone formation was found, while the
cortex itself contained damaged osteocytes. At later time-points, new bone
formation was also found at the cortical level itself. Differences between groups
were found mainly in this new bone formation process, with larger reactions for
the endosteal and periosteal bone in the loaded group after 28 and 42 days,
respectively. At the end-point of the experiment, bone formation at the cortical
level was reduced in the loaded group compared with the control group.
CONCLUSIONS: These results show that the immediate loading protocol caused no
Ding X, Zhu XH, Liao SH, Zhang XH, Chen H.
Department of Stomatology, The First Affiliated Hospital of Wenzhou Medical
College, Wenzhou, Zhejiang Province, China. firstname.lastname@example.org
implants for immediate loading and to analyze stress distribution in bone around
implants of different diameters. MATERIALS AND METHODS: Three mandible models,
embedded with thread implants (ITI, Straumann, Switzerland) with diameters of
3.3, 4.1, and 4.8 mm, respectively, were developed using CT scanning and
self-developed Universal Surgical Integration System software. The von Mises
stress and strain of the implant-bone interface were calculated with the ANSYS
software when implants were loaded with 150 N vertical or buccolingual forces.
RESULTS: When the implants were loaded with vertical force, the von Mises stress
concentrated on the mesial and distal surfaces of cortical bone around the neck
of implants, with peak values of 25.0, 17.6 and 11.6 MPa for 3.3, 4.1, and 4.8 mm
diameters, respectively, while the maximum strains (5854, 4903, 4344 muepsilon)
were located on the buccal cancellous bone around the implant bottom and threads
of implants. The stress and strain were significantly lower (p < 0.05) with the
increased diameter of implant. When the implants were loaded with buccolingual
force, the peak von Mises stress values occurred on the buccal surface of
cortical bone around the implant neck, with values of 131.1, 78.7, and 68.1 MPa
for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains
occurred on the buccal surface of cancellous bone adjacent to the implant neck,
with peak values of 14,218, 12,706, and 11,504 microm, respectively. The stress
of the 4.1-mm diameter implants was significantly lower (p < 0.05) than those of
3.3-mm diameter implants, but not statistically different from that of the 4.8 mm
implant. CONCLUSIONS: With an increase of implant diameter, stress and strain on
the implant-bone interfaces significantly decreased, especially when the diameter
increased from 3.3 to 4.1 mm. It appears that dental implants of 10 mm in length
for immediate loading should be at least 4.1 mm in diameter, and uniaxial loading
to dental implants should be avoided or minimized.
Mangano C, Piattelli A, Mangano F, Perrotti V, Iezzi G.
Dental School, University of Varese, Italy.
sites has recently been proposed as a novel but challenging surgical approach.
However, histological evidence and comparative data are still missing. The aim of
this study was an histological and histomorphometrical comparison of submerged
and immediately loaded dental implants with a new modified acid etched surface
inserted into postextraction sites of nonhuman primates. MATERIALS AND METHOD:
Thirty-two implants were placed in postextraction sockets of 4 adult Chacma
Baboons (papio ursinus). Each baboon received 8 implants: 4 submerged and 4
immediately loaded. The implants were retrieved after 90 days of healing with a
4-mm trephine bur and processed for histology and histomorphometry. RESULTS: The
bone-to-implant contact percentage in the submerged and immediate loaded implants
was 86.02% and 86.85%, respectively, with no statistically significant
differences. In the immediately loaded implants a greater amount of ongoing
remodeling was observed. CONCLUSIONS: Immediate loading seemed to be a valid
alternative to conventional technique when a implant is inserted into
postextraction sockets. Further comparative studies on a greater number of
samples are necessary to confirm our findings.
Clinical viability of immediate loading of dental implants: part I--factors for success.
Goiato MC, Pellizzer EP, dos Santos DM, Barão VA, de Carvalho BM, Magro-Filho O,
Garcia IR Jr.
UNESP--Araçatuba Dental School, Dental Materials and Prosthodontics, José
Bonifácio, 1193, Araçatuba, São Paulo 16015-050, Brazil. email@example.com
over 40 years. The evolution of surgical techniques, development of diagnostic
methods, knowledge about tissue biology, and quality of implants regarding design
and surface supported studies with 1 surgical stage followed by immediate
prosthesis placement. However, several factors influence the treatment success
with immediate loading. So, this study aimed to evaluate some factors regarding
Bone quality and the immediate loading of implants-critical aspects based on literature, research, and clinical experience.
Division of Periodontology, Eastman Department of Dentistry, University of
Rochester, Rochester, NY 14620, USA. Georgios_Romanos@urmc.rochester.edu
international literature and the requirements for long-term success are