HOME PERIO TOPICS 

HOME Implant Home 

• Giannobile, et al. Bone as a Tissue (CH 4). Clinical Periodontology and Implant Dentistry, Lindhe, J.; Lang, K. 5th Edition, 2008, Blackwell Munksgaard (Volume 1).

• Lindhe, Berglundh, Lang. Osseointegration (CH 5). Clinical Periodontology and Implant Dentistry, Lindhe, J.; Lang, K. 5th Edition, 2008, Blackwell Munksgaard (Volume 1).

1. Boioli L et al: A meta-analytic, quatitative assessment of osseointegration establishment and evolotuin of submerged and non-submerged endosseous titanium oral implants. Clin Oral Implants Res. 12: 579-88, 2001 (Duplicate from Implant I)

2. Albrektsson T et al: The long term efficacy of currently used dental implants: A review and proposed criteria of success. Int J Oral Max Implants 1:11-26, 1986 (Duplicate from implant I)

3. Albrektsson, T et al: Biological aspects of implant dentistry: Osseointegration. Periodontology 2000 4:58-73, 1994

4. Trisi, P., Rebaudi A: Progressive bone adaptaion of titanium implants during and after orthodontic load in humans. Int J Periodontics Restorative Dent. 2002 Feb; 22(1):31-43

5. Abrahamsson I, Berglundh, T, et al. Early bone formation adjacent to rough and turned endosseous implant surfaces. An experimental study in the dog Clinical Oral Implants Research, 15 (2004), pp. 381–392

6. Berglundh T, Abrahamsson I, et al. Bone healing at implants with a fluoride-modified surface: an experimental study in dogs. Clinical Oral Implants Research, 18 (2007), pp. 147–152

7. Mathieu V, Vayron R, et al. Biomechanical determinants of the stability of dental implants: Influence of the bone-implant interface properties. J Biomech. 2014 Jan 3;47(1):3-13. doi: 10.1016/j.jbiomech.2013.09.021. Epub 2013 Oct 10.

8. Greenstein G, Cavallaro J, Tarnow D. Assessing bone’s adaptive capacity around dental implants: a literature review. J Am Dent Assoc. 2013 Apr;144(4):362-8.

9. Mangano C, Piattelli A, et al. Evaluation of peri-implant bone response in implants retrieved for fracture after more than 20 years of loading. A case series. J Oral Implantol. 2013 Aug 21. [Epub ahead of print]

10. Barewal R et al: Resonance Frequence Measurment on Implant Stability in Vivo on Implants with a Sandblasted and Acid – Etched Surface. Int J Oral Maxillofac Implants 2003; 18:641-651

11. Alsaadi, G et al: A Biomechanical assessment of the relation between the oral implant stability at insertion and subjective bone quality assessment . J Clin Periodontol 2007; 34:359-366

Topic: Platform-Switched laser-microchannel implants          assessment of osseointegration

Authors:Boioli L et al

Title: A meta-analytic, quantitative assessment of osseointegration establishment and evolution of submerged and non-submerged endosseous titanium oral implants

Source: Clin Oral Implants Res. 12: 579-88, 2001
Type: Meta-analysis

Rating: Good

Keywords: dental implants, submerged, non-submerged, life table analysis, survival rates, review

Background: Two implant placement methods are used in oral implantology: submerged (S, two-stage surgical procedure) and non-submerged (NS, one-stage surgery). However, a quantitative assessment of their influence on implant osseointegration, summarising the whole present experience, is not directly possible, owing to the lack of normalisation of the published results

Purpose: to help improve the quantitative assessment of this influence by defining normalisation criteria, which would allow the pooling of the results of the studies meeting them and, hence, the statistical treatment of the overall longitudinal results.

Methods:

• A survey of the literature was performed on studies report on implants placed either with a submerged (S) or a non-sub- merged (NS) procedure. Only root-analogue, threaded implants, exclusively made of titanium, were considered.

• Among the studies meeting all criteria, 65 concerned S implants and 18 NS implants. One study concerned both S and NS implants.

• Survival life tables are established (up to 15 and 10 years respectively for S and NS implants placed in normal situations) for extended samples (13049 S and 5515 NS implants).

• Early (before loading) failure rates and 95% confidence level ranges of cumulative implant survival rates (CSR) have been evaluated.

Results:

• Both categories match current survival requirements, but with a quite different behavior over time.

• NS implants, while osseointegrating better initially, are subject to causes of osseointegration loss, which persist over a longer period of time.

• Implant design characteristics (including the type of surface) seem to be more relevant than the placement procedure for the implant’s behavior.

Conclusion:

• S and NS implants give acceptable results in terms of survival, and for both categories (but especially for S implants) the placement stage remains a discernible individual cause of failure

• S implants have been studied more than NS implants, and present less dispersed results; NS implants are particularly affected by a reduced sample after 5–6 years of observation: the findings for this period still require confirmation;

• NS implants seem to show a better osseointegration establishment, but, unlike S implants, an osseointegration loss process lasting for a longer period of time; subject to further confirmation, the type of placement procedure seems to be of lesser importance for the behavior of the implants, compared with implant design characteristics, including those related to their surface.

Topic: Implant Success

Authors: Albrektsson T, Zarb, Worthington, Eriksson

Tittle: The long term efficacy of currently used dental implants: A review and proposed criteria of success.

Source: Int J Oral Max Implants

Type: Discussion article

Rating: Fair

Keywords: success, osseointegration

Purpose: This paper is an attempt to evaluate currently used dental implant systems and to propose criteria of success.

Discussion:

Observations:

Osseointegration: is a histological definition, and only partially a clinical and radiographic one. An implant can only be judged as osseointegrated in the context of a continuum of observation, since undermining interfacial changes may be gradual, and not evident at the radiographic resolution level at least in the short term. 


Topic:microscopic evaluation ofosseointegration

Authors:Albrektsson T, Johansson C, Sennerby L

Title:Biological aspects of implant dentistry: Osseointegration.

Source:Periodontology 2000 4:58-73, 1994

Type:Discussion/Review

Rating:Good

Keywords:osseointegration

Purpose: To analyze current knowledge on osseointegration.

Discussion:

Radiographic evaluation:

Due to the surrounding bone tissue, an implant may seem to be in direct bone contact even though there is obvious soft tissue coat in reality. The maximal resolution level of radiography, under ideal conditions, is 0.1 mm, which is 10 times the size of a soft tissue cell.

Light microscopic investigations of bone-to-implant interface:

The use of modern cutting and grinding techniques has clearly demonstrated that direct bone-to-implant contact at the light microscopic resolution level is possible with many different metallic and ceramic materials. In loaded clinical cases there are indications that what is referred to as osseointegration depends on material used as one of several factors being important for implant take.

Ultrastructural investigation of experimental implants:

Ultrastructural analysis of the implant-bone interface is technically very difficult, since ultrathin sections are needed for transmission electron microscopy. Most ultrastructural investigations have been performed in animals using metal-coated polycarbonate implants, which permits sectioning, or metal plugs from which the tissue has been separated before sectioning.

Comments on published ultrastructural investigations:

The in vivo interface scenario seems to be completely different from that observed in vitro. In vitro the only cells in direct contact with the implant surface were red blood cells and macrophages, during the early healing phase, and later, multinuclear giant cells. The inner most interface was the last area to be mineralized, and this process seemed to be acellular. The amorphous layer, and in some instance the electron-dense layer, cold be distinguished before extracellular matrix became mineralized.

The commercially pure titanium bone interface in relation to other interfaces:

The interface descriptions found in the literature point to a variability of the interface morphology both for bone-bonding (hydroxyapatite or bioglass) and non-bone-bonding materials (titanium), which is why this type of classification cold be criticized.

The ultrastructure of the bone-titanium interface:

There is one type of amorphous layer in the bone-to-metal interface, even if the width and the content (mineral, collagen, and proteoglycans) has been debated.

Evaluation of retrieved oral implants removed despite a remaining anchorage:

In general, a nonmineralized amorphous layer 200-400 nm wide was bordering the mineralized bone with an electron-dense lamina limitans-like line (50 nm thick). Areas with nonmineralized tissue containing collagen and sometimes osteocytes or vessels were present along the interface.

Conclusion: The only acceptable mode of defining osseointegration is based on clinical examination finding stable implants: a process in which clinically asymptomatic rigid fixation of alloplastic materials is achieved and maintained in bone during functional loading.

Topic: Anatomy       bone adaptaion

Authors: Trisi, P., Rebaudi A

Title:Progressive bone adaptaion of titanium implants during and after orthodontic load in humans.

Source: Int J Periodontics Restorative Dent. 2002 Feb; 22(1):31-43

Type: Histology

Rating: Good

Keywords: orthodontics, implants

Purpose: To evaluate implant stability and peri-implant bone reaction by histologic and clinical evaluation after therapeutic orthodontic loads.

Methods: 41 adult patients received titanium implants (Exacta) as an orthodontic anchorage device; 12 patients received a retromolar or palatal implant to obtain tooth movement. Seven implants were removed at the end of the orthodontic therapy, after 2, 4, 6, and 12 months of orthodontic load, and processed for histologic examination.

Results: It was possible to distalize maxillary and mandibular molars and a group of teeth (molars and premolars), and to obtain tipping, uprighting, intrusion, extrusion, and transfer of anchorage in other parts of the mouth. The results showed that orthodontic therapy is facilitated and quickened using implants. All implants remained stable in the bone up to 12 months of loading, and all were osseointegrated. Microfractures, microcracks, and microcalli were observed around implants that had been placed in both low- and high-density bone. The remodeling rate was still elevated after 18 months.

Conclusion: Loading implants after 2 months of healing was shown to be safe and is considered the standard for orthodontic implants.

Topic: Osseointegration

Title: Early bone formation adjacent to rough and turned endosseous implant surfaces. An experimental study in the dog

Author: Abrahamsson I, Berglundh, T, et al.

Source: Clinical Oral Implants Research, 15 (2004), pp. 381–392

Type: Histologic study, animal model

Rating: Good

Keywords: SLA, osseointegration, implant surface

Objective: To validate a proposed model (as proposed by Berglundh et al. 2003) and to evaluate the rate and degree of osseointegration at turned (T) and sand blasted and acid etched (SLA) implant surfaces during early phases of healing.

Methods: Twenty Labrador dogs received totally 160 experimental devices (solid screw implant with either a SLA or a T surface configuration) as to evaluate healing between 2h and 12 weeks. Histometric and morphometric analyses were performed.

Results: The sections provided an overview of the various phases of tissue formation, while the decalcified, thin sections enabled a more detailed study of events involved in bone tissue modeling and remodeling for both SLA and T surfaces. The initially empty wound chamber became occupied with a coagulum and a granulation tissue that was replaced by a provisional matrix. The process of bone formation started already during the first week. The newly formed bone present at the lateral border of the cut bony bed appeared to be continuous with the parent bone, but on the SLA surface woven bone was also found at a distance from the parent bone. Parallel-fibered and/or lamellar bone as well as bone marrow replaced this primary bone after 4 weeks. In the SLA chambers, more bone-to-device contact, more initial woven bone and earlier lamellar bone formation was found than in the T chambers.

Conclusions:Osseointegration represents a dynamic process both during its establishment and its maintenance. While healing showed similar characteristics with resorptive and appositional events for both SLA and T surfaces, the rate and degree of osseointegration were superior for the SLA compared with the T chambers.

Topic:  Osseointegration

Authors: Berglundh T, Abrahamsson I, et al.

Title: Bone healing at implants with a fluoride-modified surface: an experimental study in dogs.

Source: Clinical Oral Implants Research, 18 (2007), pp. 147–152

Type:Animal study

Rating:Good

Keywords:dental implants, histology, osseointegration, titanium

Purpose: Study early stages of osseointegration to implants with a fluoride-modified surface.

Methods: Six mongrel dogs, about 1-year old, were used. All mandibular premolars and the first mandibular molars were extracted. Three months later, mucoperiosteal flaps were elevated in one side of the mandible and six sites were identified for implant placement. The control implants (MicroThread) had a TiOblast surface, while the test implants (OsseoSpeed) had a fluoride-modified TiOblast surface. Both types of implants had a similar geometry, a diameter of 3.5 mm and were 8 mm long. Following installation, cover screws were placed and the flaps were adjusted and sutured to cover all implants. Four weeks after the first implant surgery, the installation procedure was repeated in the opposite side of the mandible. Two weeks later, biopsies were obtained and prepared for histological analysis. The void that occurred between the cut bone wall of the recipient site and the macro-threads of the implant immediately following implant installation was used to study early bone formation.

Results:The amount of new bone that formed in the voids within the first 2 weeks of healing was larger at fluoride-modified implants (test) than at TiOblast (control) implants. It was further observed that the amount of bone-to-implant contact that had been established after 2 weeks in the macro-threaded portion of the implant was significantly larger at the test implants than at the controls.

Conclusions:It is suggested that the fluoride-modified implant surface promotes osseointegration in the early phase of healing following implant installation.

Topic: biomechanical determinants of implant stability

Authors: Mathieu V, Vayron R, et al.

Title:Biomechanical determinants of the stability of dental implants: Influence of the bone-implant interface properties.

Source: J Biomech. 2014 Jan 3;47(1):3-13. doi: 10.1016/j.jbiomech.2013.09.021.

Type: review

Rating: good

Keywords: Biomechanical properties; Bone; Implant; Osseointegration; Stability

Background: Dental implants are widely used however, risks of failure are still experienced and remain difficult to anticipate. The stability of biomaterials inserted in bone tissue depends on multiscale phenomena of biomechanical (bone-implant interlocking) and of biological (mechanotransduction) natures.

Purpose: to provide an overview of the biomechanical behavior of the bone-dental implant interface as a function of its environment by considering in silico (via computer simulation), ex vivo and in vivo studies including animal models as well as clinical studies.

Discussion:

Description of the bone-implant interface: the interface has a complex nature due to (i) its roughness, (ii) the fact that bone is in partial contact with the implant, (iii) adhesion phenomena between bone and the implant and (iv) the time-evolving nature of the interface properties.

• Geometrical description; bone-implant distance and micromotions: When primary stability is not sufficient, micro-movements may appear preventing good healing conditions and leading to the formation of fibrous tissue and to surgical failure. Some studies show that micromotion should not exceed 150 µm, however the precise threshold is not yet known.

• Mechanical description: stresses and the interface; When functional loading exerted via the implant exceeds “a certain stress”, the implant is regarded as being “overloaded”, leading to possible complications such as peri-implant bone resorption. However, stresses below that are beneficial for the implant outcome and stimulate bone remodeling phenomena. The determination of the value of that threshold remains unclear.

• Dynamic description: bone remodeling and osseointegration; implant osseointegration was discovered by Branemark. Diagram bellow shows the multi-scale and multi-time nature of the different phenomena occurring during osseointegration; Factors related to implant properties (dashed lines), to the surgeon (dotted line) and the ones relating to bone properties (solid lines).

Implant stability: a space-time multiscale issue

• Measurement of the multiscale bone properties around the interface:

  • Histology: the gold standard measurement.

  • Small angle X-ray scattering (SXAS): is used to assess thickness, orientation, and shape/arrangement of the mineral crystals in bone tissue. Gives information about bone mineralization but no information about mechanical properties

  • Nanoindentation: investigates biomechanical properties in the microscopic scale. Has shown that Young’s modulus and hardness values are lower in the vicinity of the implant than in mature bone.

  • Scanning Acoustic Microscopy (SAM): qualitative assessment of the biomechanical microstructural properties of bone-implant interface

  • Micro Brillouin scattering: uses the photo acoustic interaction between a laser beam and a sample to measure bone speed of sound

• Homogenization approaches of bone tissue around the interface: homogenization techniques have been developed to climb the hierarchy of scales in newly formed bone tissue, from the nanoscale up to the macroscopic level.

• Multiscale biomechanical modeling of the bone-implant interface: Various approaches have been developed to model the mechanical behavior of the bone–implant interface such as; Finite element methods (FEM), Frictional coulomb law, non-linear anisotropic FEM, …

Implant stability assessment

• X-ray and MRI based techniques: Limited resolution of clinical X-ray based techniques due to metal artifacts related to the presence of the implant metallic components. MRI has also been proposed but is also of limited interest due to magnetic fields disturbance. Maximum resolution level of radiography is 0.1mm which is ten times the size of a soft tissue cell. X-ray or MRI based techniques are not commonly used in order to assess the biomechanical properties of bone to implant interface

• Invasive biomechanical methods: Tensional test, Push out/Pull out test, Removal torque analysis

• Non-invasive biomechanical methods:

  • Empirical approaches; Hitting the implant with an instrument and listen to the noise made by the system. Insertion torque during the surgical procedure.

  • Impact based approaches: PerioTest device (Schulte et al. 1980) was originally used for evaluation of tooth mobility. Measurement leads to PerioTest value (PTV), -8 to 50. PTV correlates to mobility and level of marginal bone.

  • Resonance frequency analysis: Measurement of the first resonance frequency of the bone–implant system. Uses an L-shaped transducer or a “Smartpeg”, which is a piece screwed in the implant abutment. Measurement gives an index called Implant Stability Quotient (ISQ 0-100), system is commercialized under the name Osstell. A correlation was shown between initial ISQ value and; (i) cutting torque, (ii) bone measurements assessed empirically by the surgeon during implant placement, (iii) Cortical bone thickness, (iv) Anatomical region of implantation. Limitations:

• Only captures the first resonance frequency, which is of limited value from a structural mechanics point of view (“oversimplification”)

• Sensitivity of ISQ value to the implant stability depends on the implant type

• Relationship between ISQ values and BIC remains unclear

• Fixation and orientation of the transducer (or smartpeg) influence significantly the ISQ values

• ISQ values are related to the bone properties at the scale of the organ, but properties at the scale of 50-200μm are critical for osseointegration

• Quantitative ultrasounds methods: Used to assess bone mineral status, enamel thickness. Several studies show the potentiality of QUS to investigate bone quality around implants, further work is necessary.

Topic:Bone           adaptive capacity

Author:Greenstein G, Cavallaro J, Tarnow D.

Title: Assessing bone’s adaptive capacity around dental implants: a literature review.

Source:J Am Dent Assoc. 2013 Apr;144(4):362-8

Type:Review

Reviewer: Phillip Crum

Rating: Good

Keywords:Bone; dental implants; osseointegration; resorption

Purpose:To review concepts pertaining to bond adaptation that may account for high survival rates of prostheses that are subjected to increased stresses.

Discussion:

Bone Mechanotransduction

• Mechanotransduction=the mechanism that permits bone to detect stimuli.

• It is thought that bone cells sense and respond to their mechanical environment by changing their biological and biochemical actions.

• It is strain, not stress, that precipitates alteration of the bone response

• 3 Possible stimuli for Osteocytes

  • 1-Direct mechanical stimulation

  • 2-Fluid flow induced by shear stress

  • 3-Bone Microdamage

• The prevailing concept suggests that under dynamic loading, bone matrix deformation produces an interstitial fluid flow. This flow creates shear stress that stimulates osteocytes. Osteocytes act as mechanosensors and convey signals to adjacent cells (osteoblasts) through the intercellular communication network.

Rules For Bone Adaptation to Mechanical Stimuli

• According to Turner, the following 3 rules characterize the response of bone to stress

  • Bone adaptation is determined by dynamic, rather than static, loading, and it is the alteration of stress, not its consistency, that produces bone modifications

  • A short episode of mechanical loading is required to begin the adaptive response

  • Bone cells accommodate to customary mechanical loading, making them less responsive to routine loading signals.

• From these, it can be deduced that abnormal stress and strains drive structural change.

Stresses and Strains on Bone

• Magnitude of occlusal load, cycle number, direction and frequency all can affect the quantity of stress.

• The relationship between stress and strain establishes the modulus of elasticity (stiffness) of a material.

• According to Frost, a certain amount of stress is required to maintain bone homeostasis.

  • Microstrains from 0 to 50atrophy

  • 50 to 1500normal bone modeling

  • 1500 to 3000overload

  • >3000possible destruction

Bone Microdamage

• Fatigue: bone has lost strength and stiffness due to repetitive loads.

• Microcracks: a discontinuity in the calcium-rich matrix and reflects fissures and breaks in the hydroxyapatite.

Bone’s Proliferative response to stress around dental implants

• If the load is above a certain threshold, bone loss or loss of osseointegration can occur.

• If functional load is below a destructive threshold, it can be stimulatory and induce apposition of bone and increased osseous density.

• There is much evidence that supports the concept that bone can respond to stress and modify itself to withstand increased mechanical forces.

Remodeling

• Jee estimated that about 20 percent of the cortical and cancellous bone surfaces (endosteal and periosteal) are remodeling at any point in time.

• The replacement rate of cortical bone is 7.7% per year

• The replacement rate of cancellous bone is 17.7% per year

• Garetto showed that within 1mm of implants, there was a layer of bone that remodeled rapidly. The turnover rate was three to nine times faster per year within the 1mm of the implants.

• Bones such as the mandible that experience loading from varying directions exhibit more platelike trabecular architecture. An advantage of this structure is its ability to manage forces from different directions.

• High load areas usually manifest dense platelike architecture, whereas low load areas usually demonstrate low-density rodlike structures.

Conclusion: There are 2 possible explanations for the success of prosthetic constructs. First, is that bone is stronger than expected and can tolerate increased stress. Second is that as long as the stress/strain level does not increased beyond a threshold that causes bone destruction, bone has the ability to remodel and model and increase its osseous density.

Topic: Fracture

Authors: Mangano C, Piattelli A, Mortellaro C, Mangano F, Perroti V, Iezzi G

Title: Evaluation of peri-implant bone response in implants retrieved for fracture after more than 20 years of loading. A case series

Source:J Oral Implantol. 2013 Aug 21

Type: Case series

Rating: Good

Keywords: Bone remodeling, human histology, implant surfaces, retrieved dental implants

Purpose: To present a histological case series of the peri-implant bone responses in implants retrieved for fracture after more than 20 years loading period.

Methods: 5 implants retrieved for bodily fracture in 5 patients were found to be analyzed. The surface of these implants was obtained by sandblasting, followed by acid-etching for 30 minutes. The implants were then washed with hydrogen peroxide and dried with high heat. None of the implants were immediately loaded. In 3 cases, implants supported partial fixed bridges, while in 2 cases there was a mandibular ovendenture supported by 2 implants. Four implants were located in the mandible, and 1 in the maxilla. All implants were retrieved with a 5-mm trephine bur. Histological analysis and histomorphometry of the percentages of bone-implant contact were carried out.

Results: Compact, mature bone in close contact with the implant surface was observed in all specimens, with no gaps or connective tissue at the interface. Primarily newly formed bone was observed in proximity of the implant surface. In the most coronal portion of one implant, connective tissue adhering to the implant surface was detected. Bone-to-implant contact percentage ranged from 37.2-76%.

Conclusion: Implant effectiveness is largely dependent on biological stability and integration between bone and implant. Endosseous implants may function over a wide range of degrees of osseointegration.

Topic:sandblasted and acid-etched implant surfaces
Authors:Barewal R et al.
Title: Resonance frequency measurement of implant stability in vivo on implants with a sandblasted and acid-etched surface.

Source: J Oral Maxillofac Implants 2003; 18:641-651

Type: Clinical Study

Rating: Good

Keywords: bone, clinical trials, dental implants, early healing, endosseous dental implantation,

implant stability, resonance frequency analysis

Purpose: to understand pattern of stability changes and early healing around single-stage roughened-surface implants during the first 2 ½ months in different bone types.

Methods: Twenty patients had 1 to 4 implants placed in the posterior maxilla or mandible. Bone type was classified into 1 of 4 groups according to the Lekholm and Zarb index (1985). RFA was used for direct measurement of implant stability on the day of implant placement and consecutively once per week for 6 weeks and at weeks 8 and 10.

Results:

Conclusion: The lowest values for interfacial stiffness between the bone and the implant were found at 3 weeks, particularly in type 4 bone. Healing responses of Types 2 and 3 bone were more similar to Type 1 than to Type 4 bone. The RF values at 6 weeks did not differ from those at 10 weeks in all bone types; this supports the idea of a 6-week healing period for ITI implants in Types 1, 2, and 3 bone. The lack of significant change in stability from 5 to 10 weeks for Types 1, 2, and 3 bone supports further testing of an even shorter healing protocol. With regards to Type 4 bone, the current 12- week healing period could be evaluated and potentially shortened.

Topic: implant stability per bone type

Authors: Alsaadi G, Quirynen M, Michiels K, Jacobs R, Steenberghe D

Title:A biomechanical assessment of the relation between the oral implant stability at insertion and subjective bone quality.

Source: Journal of Clinical Periodontology 2007; 34: 359-366.

Type: Clinical

Reviewer: Cynthia Goldin

Rating: Good

Keywords:biomechanics; bone quality; dental implants; insertion torque; oral implants; osseointegration; periotest; RFA

Purpose:To evaluate the validity of subjective bone quality assessment.

Methods:A total of 298 patients treated with implants. Bone quality assessment performed immediately after implant placement and using the Lekholm & Zarb index. Tactile sensation was assessed for cortical bone and trabecular bone during high speed drilling. A scale from 1 (very thick cortex/dense trabecular bone) – 3 / 4 (thin/ poorly mineralized trabecular bone). The bone quality was assessed during implant insertion by an electronic torque force measurement device, which measures the torque force while tapping or inserting the implant at slow speed. The rigidity of implant-bone continuum was assessed by resonance frequency analysis taken at implant insertion and before abutment insertion, through a peg attached to the fixture, and an ISQ value is presented. This runs from 1-100, the higher the ISQ the more stable the implant. Periotest also measured the rigidity. After connecting a temporary abutment 4 mm in length, this device measures the damping capacity of the implant bone continuum. A rod is placed perpendicular to the abutment at a distance of 2 mm and it is accelerated electromagnetically. When rod hits the implant, it is decelerated. The faster the deceleration, the greater implant stability. Values range from -8 (very stable) to +50 (extremely mobile).

Results:Subjective assessment was related to PTV, ISQ and placement torque in the crestal, the second and the apical third.

ISQ and PTV were also compared with the bone quality assessed according to the Lekholm & Zarb index. A significant relationship was detected.

– Grade 1: 5.3, 73.3

– Grade 3 or 4: 1.6, 55

ISQ and PTV recorded at implant insertion were also compared with the bone quality assessed according to the surgeon’s tactile sensation. A significant relationship was detected between ISQ, PTV and cortical bone grades and between ISQ and trabecular bone grades

For surgeon’s tactile sensation, a good correlation was noted for the presence of a thick cortex: – 4.6, 70.3 or a thin one: – 0.3, 65.9. For dense trabecular bone, the values were – 2.8, 69.4 while for poor trabecular bone, the values were – 1.7, 66.4

Conclusion:

Subjective assessment of bone quality is related to PTV, ISQ and placement torque measurements at implant insertion.

DesignedBy StevenJ. Spindler, DDS LLC

HOME Implant Home 

Longitudinal studies: survival and success of implants

• Lang and Salvi. Implants in Restorative Dentistry (CH 52). Clinical Periodontology and Implant Dentistry, Lindhe, J.; Lang, K. 5th Edition, 2008, Blackwell Munksgaard (Volume 2).

• Misch. Rational for Dental Implants. (CH 1). pp 3-25. Contemporary Implant Dentistry, Misch, C.E., 3rd Edition, 2008, Mosby Year Book.

• Cochran, D: Implants Therapy I. Proceeding of the 1996 World Workshop in Periodontics 1:707-795, 1996

• Fritz, M: Implants Therapy II. Proceedings of the 1996 World Workshop in Periodontics 1: 796-815,1996

1. Boioli L et al: A meta-analytic, quatitative assessment of osseointegration establishment and evolution of submerged and non-submerged endosseous titanium oral implants. Clin Oral Implants Res. 12: 579-88, 2001

2. Albrektsson T et al: The long term efficacy of currently used dental implants: A review and proposed criteria of success. Int J Oral Max Implants 1:11-26, 1986

3. Misch CE, Perel ML, Wang HL, et al. Implant success, survival, and failure: the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference. Implant Dent. 2008 Mar;17(1):5-15.

4. Klokkevold P et al: Current status of dental implants: A periodontal perspective. Int J Oral Maxillofac Implants 15: 56-65, 2000

5. Salinas TJ, Eckert SE. In patients requiring single-tooth replacement, what are the outcomes of implant- as compared to tooth-supported restorations? Int J Oral Maxillofac Implants. 2008 Jan-Feb;23(1):56.

6. Simonis P, Dufour T, Tenenbaum H. Long-term implant survival and success: a 10-16-year follow-up of non-submerged dental implants. Clin Oral Implants Res. 2010 Jul;21(7):772-7.

7. Ueda T, Kremer U, Katsoulis J, Mericske-Stern R. Long-term results of mandibular implants supporting an overdenture: implant survival, failures, and crestal bone level changes. Int J Oral Maxillofac Implants. 2011 Mar-Apr;26(2):365-72.

Topic: Platform-Switched laser-microchannel implants      submerged and non-submerged implants

Authors: Boioli L et al

Title: A meta-analytic, quatitative assessment of osseointegration establishment and evolution of submerged and non-submerged endosseous titanium oral implants

Source: Clin Oral Implants Res. 12: 579-88, 2001
Type: Meta-analysis

Rating: Good

Keywords:dental implants, submerged, non-submerged, life table analysis, survival rates, review

Background: Two implant placement methods are used in oral implantology: submerged (S, two-stage surgical procedure) and non-submerged (NS, one-stage surgery). However, a quantitative assessment of their influence on implant osseointegration, summarising the whole present experience, is not directly possible, owing to the lack of normalisation of the published results

Purpose: to help improve the quantitative assessment of this influence by defining normalisation criteria, which would allow the pooling of the results of the studies meeting them and, hence, the statistical treatment of the overall longitudinal results.

Materal and methods:

• A survey of the literature was performed on studies report on implants placed either with a submerged (S) or a non-sub- merged (NS) procedure. Only root-analogue, threaded implants, exclusively made of titanium, were considered.

• Among the studies meeting all criteria, 65 concerned S implants and 18 NS implants. One study concerned both S and NS implants.

• Survival life tables are established (up to 15 and 10 years respectively for S and NS implants placed in normal situations) for extended samples (13049 S and 5515 NS implants).

• Early (before loading) failure rates and 95% confidence level ranges of cumulative implant survival rates (CSR) have been evaluated.

Results:

• Both categories match current survival requirements, but with a quite different behavior over time.

• NS implants, while osseointegrating better initially, are subject to causes of osseointegration loss, which persist over a longer period of time.

• Implant design characteristics (including the type of surface) seem to be more relevant than the placement procedure for the implant’s behavior.

Conclusion:

• S and NS implants give acceptable results in terms of survival, and for both categories (but especially for S implants) the placement stage remains a discernible individual cause of failure

• S implants have been studied more than NS implants, and present less dispersed results; NS implants are particularly affected by a reduced sample after 5–6 years of observation: the findings for this period still require confirmation;

• NS implants seem to show a better osseointegration establishment, but, unlike S implants, an osseointegration loss process lasting for a longer period of time; subject to further confirmation, the type of placement procedure seems to be of lesser importance for the behavior of the implants, compared with implant design characteristics, including those related to their surface.

Topic:Implant Success

Authors:Albrektsson T, Zarb, Worthington, Eriksson

Tittle: The long term efficacy of currently used dental implants: A review and proposed criteria of success.

Source: Int J Oral Max Implants

Type: Discussion article

Rating: Fair

Keywords: success, osseointegration

Purpose: This paper is an attempt to evaluate currently used dental implant systems and to propose criteria of success.

Discussion:

Observations:  Osseointegration: is a histological definition, and only partially a clinical and radiographic one. An implant can only be judged as osseointegrated in the context of a continuum of observation, since undermining interfacial changes may be gradual, and not evident at the radiographic resolution level at least in the short term. 


Topic:Implant success, survival, and failure

Authors:Misch CE, Perel ML, Wang HL

Title:Implant success, survival, and failure: the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference.

Source:Implant Dent. 2008 Mar;17(1):5-15.

Type:Consensus discussion

Rating:Good

Keywords:implant clinical success, implant clinical survival, implant clinical failure

Purpose: To propose 4 clinical categories that contain conditions of implant success, survival, and failure.

Discussion:

Survival conditions:

Satisfactory survival: an implant with less than ideal conditions, yet does not require clinical management

Compromised survival: implants with less than ideal conditions, which require clinical treatment to reduce the risk of implant failure

Implant failure: implants that require removal or have already been lost

Implant success: should include a time period of at least 12 months loading. Early implant success is 1-3 years, intermediate 3-7 years, long term success more than 7 years

Clinical indices:

Pain: Once implant has achieved primary healing, absence of pain under vertical or horizontal forces is a primary subjective criterion. Pain should not be associated with the implant after healing. Usually, pain form the implant body does not occur unless the implant is mobile and surrounded by inflamed tissue or has rigid fixation but impinges on the a nerve. Pain during function can place the implant in the failure category. Sensitivity during function may place the implant in the survival category and may warrant clinical treatment.

Mobility: Lack of clinical movement does not mean the true absence of mobility. Lack of mobility usually means that at least a portion of the implant is in direct contact with bone, although the percentage of bone contact cannot be specified. A clinically mobile implant indicates the presence of connective tissue between the implant and bone (failure).

Radiographic crestal bone loss: The marginal bone around implant crestal region is usually a significant indicator or implant health. The Pisa Consensus suggests that the clinical assessment for each implant monitors marginal bone loss in increments of 1.0 mm. The bone loss measurement should be related to the original marginal bone level at implant insertion, rather than to a previous measurement.

Probing depths: Probing depths may be of little diagnostic value unless accompanied by signs and/or symptoms. It is of benefit to probe and establish a baseline measurement after the initial soft tissue healing around the permucosal aspect of the implant. Increases in this baseline measurement over time most often represents marginal bone loss.

Peri-implant disease: Exudate or an abscess around an implant indicates exacerbation of the peri-implant disease and possible accelerated bone loss. An exudate persisting more than 1-2 weeks usually warrants surgical revision of the peri-implant area to eliminate causative elements.

The ICOI Pisa Implant Quality of Health Scale

Conclusion:

Implant success is as difficult to describe as the success criteria for a tooth. Implant failure is easier to describe than implant success or survival and may consist of a variety of factors. Any pain, vertical mobility, and uncontrolled progressive bone loss warrant implant removal.

Topic: Periodontal considerations around dental implants

Authors: Klokkevold P et al

Title: Current status of dental implants: A periodontal perspective

Source: Int J Oral Maxillofac Implants 15: 56-65, 2000

Type: Review

Rating: Good

Keywords: dental implants

Purpose: To provide an overview of the current status of implants as related to the practice of periodontics.

Discussion:

RESTORING FORM, FUNCTION AND ESTHETICS:

The prosthetic position was not thought to be critical to the success of implants, and therefore it was not a major consideration. However due to the esthetic demands of patients, implant therapy has become increasingly focused on prosthetically driven implant position. Several new evidence-based guidelines emerged from prosthetically driven implant positioning, including the need to reconstruct hard and soft tissues that had been lost, so a bone augmentation or bone regenerative procedure had to be considered.

PERI-IMPLANT PATHOLOGY AND IMPLANT FAILURE

Peri-implant pathology, or more specifically periimplant bone loss, has been attributed to several different factors, including poor surgical management, failure to achieve osseointegration, premature loading, biomechanical overload, peri-implant infection, and impaired host response.

PERI-IMPLANT TISSUE ANATOMY FROM THE PERIODONTAL PERSPECTIVE

Osseointegrated dental implants do not have any connective tissue fiber attachments. Osseointegrated dental implants by definition do not have any soft tissues intervening between the implant surface and the bone. There are no collagen fibers attached to the implant surface. There is a connective tissue network of fibers around the implant coronal to the level of supporting bone. The supra-bony connective tissue surrounding the implant is made up of circumferential fibers that run parallel to the implant surface.

BIOLOGIC DIMENSION OF SOFT TISSUES AROUND IMPLANTS

Regardless of the type of implant used and the soft tissue dimensions at the time of placement, the authors found that a 2-mm-long junctional epithelium and a 1-mm zone of connective tissue were consistently established.

PERI-IMPLANTITIS

Peri-implantitis is defined as an inflammatory process affecting the tissues around an osseointegrated implant in function that results in loss of supporting bone, while peri-implant mucositis is an inflammatory process distinguished from periimplantitis by the lack of bone loss.

TREATMENT OF PERI-IMPLANTITIS

The most important aspect of treatment for peri-implantitis is to stop the progression of bone loss by controlling bacterial infection. As with periodontal therapy, the goal of surgical therapy is complete debridement of the defect, decontamination of the implant surface, and possibly removal of any porous implant surface coatings. Once the inflammatory disease process is controlled, it is possible to attempt regenerative procedures. In addition to bacterial infection, biomechanical overload has been shown to contribute to periimplant bone loss. Bone loss associated with biomechanical overload is most frequently found to be localized around the coronal aspect of the bone-implant interface.

Radiographs should be taken periodically to evaluate potential loss of bone. It has been well established that the amount of bone loss around Brånemark-type implants is approximately 1 to 1.5 mm in the first year after loading and 0.1 mm annually thereafter.

At regular intervals (every 3 to 6 months), implant abutment/restoration surfaces should be debrided of plaque and calculus accumulations.

Conclusion:The combination of in-depth biologic knowledge together with extensive surgical training has given the periodontist the skills to provide the highest quality care to patients around the world.

Topic:Implants vs Fixed Partial Dentures

Title: In patients requiring single-tooth replacement, what are the outcomes of implant- as compared to tooth-supported restorations?

Author: Salinas TJ, Eckert SE.

Source: Int J Oral Maxillofac Implants. 2008 Jan-Feb;23(1):56.

Type: Systematic review

Rating: Good

Keywords: comparative study, prosthodontics, implants compared to FPD, FPD, restorative planning

Purpose:The study provides a systematic review of the literature to determine the long-term survival characteristics of single implant-supported crowns and fixed partial dentures.

Materials and Methods:

A search of the MEDLINE, EMBASE, and Cochrane Collaboration databases was conducted to identify articles that compared survival and success of fixed partial dentures and single implant-supported crowns. In addition to comparative cohort studies, articles that pertained specifically to single implant-supported crowns or fixed partial dentures were included in this review. Inclusion criteria for implant and fixed partial denture articles included a minimum 2-year study, primary publication in the English language, a minimum of 12 implants, implants designed to osseointegrate, and inclusion of data regarding implant and prosthetic performance. Data were analyzed using cumulative proportions of survival and success for both prosthetic types and for individual implants. Wilson score method was used to establish 95% confidence intervals for each population. The chi-square test for homogeneity was performed.

Results: The literature search failed to identify any articles that directly compared survival or success of single implant-supported restorations with fixed partial dentures. Following the search criteria, and independent analysis by reviewers, 51 articles were identified in the implant literature (agreement, 95.42%; kappa coefficient, 0.8976), and 41 were identified in the fixed partial denture literature (agreement, 90.97%; kappa coefficient, 0.7524). Pooled success of single-implant restorations at 60 months was 95.1% (CI: 92.2%-98.0%), while fixed partial dentures of all designs exhibited an 84.0% success rate (CI: 79.1%-88.9%).

Conclusions: Tthis systematic review of the scientific literature failed to demonstrate any direct comparative studies assessing clinical performance of single implant-supported crowns and tooth-supported fixed partial dentures. The analysis suggested differences at 60 months between survival of implant-supported single crowns and natural tooth-supported fixed prostheses when resin-bonded and conventionally retained fixed prostheses were grouped. This difference disappeared when implant-supported single crowns were compared with conventionally retained fixed partial dentures at 60 months. For other time periods, direct comparative data were unavailable.

Topic: Implant survival and success rate

Authors: Simonis P, Dufour T, Tenenbaum H.

Title: Long-term implant survival and success: a 10-16-year follow-up of non-submerged dental implants.

Source: Clin Oral Implants Res. 2010 Jul;21(7):772-7.

Type: Retrospective study

Rating: Fair

Keywords: implant survival, implant success, cumulative survival rate

Purpose: To evaluate the long-term results of dental implants using implant survival and implant success as outcome variables.

Methods: Of the 76 patients who received 162 implants of the Straumann Dental Implant System during the years 1990-1997, 55 patients with 131 implants were recalled 10-16 years after implant placement for a complete clinical and radiographic examination, followed by a questionnaire that examined the degree of satisfaction. The incidence of biological and technical complications has been carefully analyzed for each implant. Success was defined as being free of all these complications over the entire observation period. Associated factors related to peri-implant lesions were analyzed for each implant.

Results: The long-term implant cumulative survival rate up to 16 years was 82.94%. The prevalence of biological complications was 16.94% and the prevalence of technical complications was 31.09%. The cumulative complication rate after an observation period of 10-16 years was 48.03%, which meant that substantial amounts of chair time were necessary following implant placement. The majority of implant losses and biological complications were concentrated in a relatively small number of patients.

Conclusion: Despite a relatively high long-term survival rate, biological and technical complications were frequent. Patients with a history of periodontitis may have lower implant survival rates than patients without a history of periodontitis and were more prone to biological complications such as peri-implant mucositis and peri-implantitis.

Topic: implant-supported overdentures

Authors: Ueda T, Kremer U, Katsoulis J, Mericske-Stern R

Title:Long-term results of mandibular implants supporting an overdenture: implant survival, failures, and crestal bone level changes

Source: Int J Oral Maxillofac Implants. 2011 Mar-Apr;26(2):365-72.

Type: clinical

Rating: good

Keywords: crestal bone loss, dental implants, implant surgical, long-term follow-up study, manifestation of failures,

Purpose:To summarize the long-term clinical observations of edentulous patients treated with mandibular implant-supported overdentures.

Methods: 147 edentulous patients, fairly healthy, admitted to treatment with mandibular implant overdentures in university of Bern, Switzerland. The treatment plan was to connect the dentures to only two implants by means of single ball anchors or bars; in patients with severely reduced ridge (≤ 8mm) or narrow and curved anterior mandible, three implants would be placed. Strauman implants in all pts. One-part implants with 7,9,11,13 or 15 mm, and two-part implants 6,8,10,12, or 14 mm, all 3.3 or 4.1 mm diameter. Non-submerged, single-stage placement, unloaded healing time 3 months then prosths fabricated. Regular maintenance care was provided at least one time per year. The cumulative implant survival rate was calculated. Implant failures were described according to clinical signs at the time of removal and related to the patient’s specific history. Crestal bone measurements were performed using computer software based on panoramic radiographs.

Results:147 patients with 314 implants were evaluated for 10 to 24 years. Of these, 101 patients were still available. Success rate could not be calculated due to absence of regular radiographs to confirm a minimum annual bone loss. Thirteen implants failed during the observation period, resulting in a cumulative survival rate of 85.9% after 24 years. The reasons for removal of implants were peri-implantitis (two implants) and mobility (11 implants). Mean crestal bone loss was 0.54 ± 0.7 mm per implant site after an average observation time of 16.5 ± 3.9 years. The duration of loading had a statistically significant effect on bone loss. NSSD among different subgroups of implants.

Conclusion:The data exhibit a satisfactory survival rate of implants. An individual analysis of implants with late failures did not reveal a typical failure pattern, but loss of implants without signs of infection was more frequent than loss of implants with signs of peri-implantitis.

DesignedBy StevenJ. Spindler, DDS LLC